Tenth Grade Science - RCCSecondaryScience -...

Tenth Grade Science

Curriculum Map

Red Clay Consolidated School District

August 2007

ACKNOWLEDGEMENTS

The Office of Curriculum and Instruction would like to thank the following people for their hard work in helping create this document:

Kathy Caligiuri: McKean High School, for working to create a usable Scope and Sequence

Kris Anania, A.I. DuPont High School

Kristine Burpee, Dickinson High

William Coughlin, McKean High

Dana Hammaker, A.I. DuPont High

TENTH GRADE SCOPE AND SEQUENCE

September

Topic Standards GLEs AssessmentSafety Right-to-know Law 1. Safety Quiz/safety

contractReading in Science/Nature of Science

1.1.1, 1.1.2, 1.1.4,1.1.5, 1.2.2

10.1.a, 10.1.d, 10.1.e Current events, personal glossary, homework from text (ongoing).

Evolution by Natural Selection

1.1.1, 1.1.6, 7.2.3, 7.2.4, 7.2.6

10.7.r, 10.7.s, 10.7.u, 10.7.v, 10.7.y, 10.7.bb,

2. State Assessment: Natural Selection, questions 1-3.

October:

Topic Standards GLEs AssessmentEvidence for evolution 7.2.1, 7.2.2, 7.2.4 10.7.t, 10.7.v, 10.7.z 3. “Chicken Wings and

Batters’ Arms” activity (from Nature of Science/Evolution) Questions 1-3.

Evolutionary mechanisms: Genetic Drift, Sexual Selection, and Natural Selection

1.1.4, 7.2.1, 7.2.3, 7.2.4, 7.2.6,

10.7.w, 10.7.x, 10.7.z, 10.7.aa

4. State Assessment: Natural Selection, question 7.

5. Assessment, Microevolution, questions 1 and 2.

November:

Topic Standards GLEs AssessmentWhy Evolution Matters Now

1.1.4, 1.1.6, 1.2.1, 1.3.1 6.1.2, 7.2.3, 7.2.5, 7.2.6, 7.2.7

10.1.d, 10.1.f, 10.7.gg, 10.6.b, 10.6.gg, 10.7.aa, 10.7.bb, 10.7.dd

6. State Assessment: Why Evolution Matters Now, Questions 1, 2c, 3b.

December:

Topic Standards GLEs AssessmentInfection and Immunity 6.1.1., 6.1.8, 6.1.10 10.6.b, 10.6.dd 7. “Search and Destroy”

Investigation Reflection (from Chemical Biology), questions 1- 3.

Molecules of Life 2.1.2, 2.4.3, 2.4.4, 2.4.6, 6.2.1,

10.6.k, 10.6.l, 10.6.m, 10.6.n

8. McMush—Summary of Activity—writing activity.

January:

Topic Standards GLEs AssessmentEnergy in Living Systems

2.3.1, 6.2.1, 6.2.2, 6.2.3, 6.2.4

10.6.q, 10.6.s, 10.6.t, 10.6.u, 10.6.v,10.6.x

9. Photosynthesis and Respiration, questions 1 (a and b only), 2b, 3.

Enzymes 1.1.1, 1.1.2, 1.1.6, 2.4.3, 2.4.4., 2.4.5, 6.2.1

10.6.y, 10.6.z, 10.6.aa Lab Report: Chemical Biology Activity 9: Investigating Enzyme Action or Lab Report: Chemical Biology Activity 10: Investigating Enzyme Action with Beano.

Midterm:

February:

Topic Standards GLEs AssessmentCells and Cell size 1.1.6, 1.2.1, 6.1.2, 6.1.3 10.6.a, 10.6.b, 10.6.c,

10.6.i10. Group assignment—the Cell. “Design a Cell”

11. Cells and Cell Size, questions 1 and 2.

Osmosis and Diffusion/Active Transport

1.1.2, 6.1.4, 6.1.5, 10.6.d, 10.6.e, 10.6.f, 10.6.g, 10.6.h

12. Osmosis and Diffusion, questions 1 and 2.

March:

Topic Standards GLEs AssessmentRegulation and Homeostasis

6.1.7, 6.1.9, 6.3.1, 6.3.2, 6.4.1, 6.4.3

10.6.j, 10.6.bb, 10.6.cc, 10.6.ff

13. Assessment—Feedback Loops questions 1-4.

April:

Topic Standards GLEs AssessmentDNA and the genetic code

6.1.6, 7.1.1, 7.1.3, 7.1.5 10.7.a, 10.7.b, 10.7.c, 10.7.d, 10.7.e, 10.7.i, 10.7.k

14. State Assessment—Patterns of Inheritance, Question 1a, 2a, 2b.

Cell Cycle and Cancer 6.4.1, 7.1.4, 7.1.9 10.6.hh, 10.7.j, 10.7.l, 10.7.m, 10.7.q,

15. Assessment: Cell cycle and Cancer questions 1-4.

Meiosis and Chromosomes

1.1.3, 1.1.4, 1.1.5, 1.2.1, 7.1.4, 7.1.6, 7.1.7, 7.1.9

10.1.c, 10.1.d, 10.1.e, 10.7.g, 10.7.n, 10.7.q

16. Assessment: Meiosis and Chromosomes, questions 1-3.

May:

Topic Standards GLEs AssessmentGenetics 7.1.1, 7.1.2, 7.1.8, 7.2.4 10.7.f, 10.7.h, 10.7.o,

10.7.x17. State Assessment: Patterns of Inheritance, questions 1, 2, 3a, 3b, 4.

Biotechnology 1.1.1, 1.1.2, 1.1.5, 1.1.6, 6.4.2, 6.4.4, 7.3.1, 7.3.2,

10.1.a, 10.1.b, 10.1.e, 10.1.f, 10.6.ee, 10.7.ff, 10.7.gg, 10.7.hh, 10.7.ii

Lab report.

Final Exam

Lab reports: Students will prepare a formal lab report on one activity from each of the three major units:

Nature of Science/Evolution:Chemical Biology:Genetics and Biotechnology:

UNDERSTANDING THE SCIENCE CURRICULUM MAPHIGH SCHOOL

Fall 2007

The Red Clay Consolidated School District is in the process of creating curriculum maps for each grade (K-12) in science. We have prepared a brief description of how the curriculum maps can be used in planning, delivering, and assessing science instruction.

Why use curriculum maps?

Beginning in August 2007, public schools in Delaware will be using the revised (2006) Delaware science standards (http://www.doe.k12.de.us/programs/pcs/science.shtml). The Science Coalition of Delaware has worked hard to create a rich science curriculum at all grades to meet these standards. The curriculum map will allow teachers to create a plan of instruction to meet these standards using curricula in which they have been trained. The map will allow teachers to adjust the pacing of their instruction to the needs of the students, the availability of resources, and the schedule of the school and district.

How are the curriculum maps organized?

I. Standards and GLEs:

The curriculum maps for each grade begin with a list of the standards for that grade cluster and the GLEs (Grade Level Expectations) for that grade. Red Clay has developed a coding system for both the standards and GLEs, and these coding systems are explained (see “Understanding the Revised Science Standards” and “Understanding the GLEs” enclosed). The standards represent the required instruction. In Delaware, the emphasis in science is on big ideas and concepts, not on memorizing facts, formulas, and other trivia. The GLEs represent the sorts of tasks, understandings, and skills we aim for our students to achieve in each grade.

II. Scope and Sequence:

Each map includes a Scope and Sequence. This is a timetable for the school year, organized by month. Listed for each month is a broad topic name, the standards (by number), the GLEs (by number) and the assessments for each topic. The Scope and Sequence is driven by the assessments. The purpose of the scope and sequence is to give an estimate of how long to spend on various topics and a rough sequence of topics. This sequence may be adjusted as needed. In every school, teachers should adjust topics of instruction to meet the needs of their students. Also, since resources are often shared among several teachers, some “juggling” of topics will always be necessary. The most important things about the Scope and Sequence are 1) the Standards must be taught, since the DSTP is a test of the Standards and 2) the Assessments (discussed below) must be administered and scored.

The order of topics on the Scope and Sequence is based on the training schedule at the Science Coalition of Delaware. Since teachers who take these trainings are expected to teach the units while in training, the Scope and Sequence reflects the Coalition’s sequence. If teachers must deviate from this sequence, this need should be discussed with the building principal and the Secondary Science Specialist. Because students sometimes change science classes during the year, it is important that they receive a consistent science program.

http://www.doe.k12.de.us/programs/pcs/science.shtml

III. Assessments:

Each topic on the Scope and Sequence has an associated assessment. The assessments are referred to by number (17 in all). The assessments come in several formats:

a. Short answer questions. A topic may have 1-4 short answer questions for students to answer. They are in the same format as short answer questions on the DSTP, and like the DSTP questions, each has a scoring option of 2 points (complete response) 1 point (partial response) and 0 (incorrect response). The rubric which describes the criteria for each is a guideline. Teachers are encouraged to determine whether or not students have met the standards from answers on the assessments.

b. Lab reports: In high school, some of the big units (for tenth grade, Nature of Science/Evolution, Chemical Biology, and Genetics/Biotechnology) may include one laboratory report. Students may work in groups on the lab investigation, but each student should submit one report. A rubric for lab reports is included.

c. Writing prompts: Some of the assessments include a writing prompt, consisting of a letter or position statement that will require more extensive design on the part of the student. The rubric for writing prompts is included with each prompt.

These are formative assessments. They may be used in a variety of ways: as a warm-up question, as a quiz or test question, or as part of a larger activity. Their purpose is to determine if students have met the standards or not. Each big unit has a checklist for the assessments. Teachers will make a copy of each checklist for each of their classes in the content area. However the assessments are used, teachers will record student results on the checklist.

Some of these assessments are taken from the Science Coalition of Delaware’s assessment website (www.scienceassessment.org). The Coalition website uses a two digit rubric to score student responses. While this is an acceptable way to score the Red Clay assessments, teachers are not required to use the two digit rubric, since it is extremely time consuming. However, if teachers require specific data about student misconceptions, they are encouraged to use the two digit rubric. Contact the Secondary Science Specialist for more information. As of August 2008, no ninth grade assessments are posted to the Coalition’s assessment website.

IV. Text References/Vocabulary: Each topic includes a mini-glossary of terms and references from the textbooks adopted by Red Clay (for biology, this book is the following:

for Physical/Earth Science (9th grade course):

Dobson, K., Holman, J., and Roberts, M. Science Spectrum Physical Science. Austin, TX; Holt, Rinehart, and Winston; 2004

for Biology (10th grade course):

Campbell, N.A., Williamson, B., and Heyden, R.J. Biology Exploring Life. Upper Saddle River; NJ, Pearson Education, Inc; 2004.

Teachers are not required to use activities out of the textbook, but many find that the textbook is a useful resource for supplemental reading. The vocabulary list includes terms that students may have difficulty

http://www.scienceassessment.org/

with, not just terms from the glossary in the textbook. The vocabulary list can be helpful for those teachers who use word walls and other vocabulary exercises.

Finally:

This curriculum map is designed to make the teacher’s job easier so the teacher can concentrate on our students. If teachers finish a topic early in a given month, they are encouraged to move on. Likewise, if a topic takes longer than indicated by the map, they should use as much time as necessary to meet the students’ needs. The Office of Curriculum and Instruction will need your feedback about how useful this map is. Any comments, questions, criticisms, or concerns (or praise) should be directed to any of the following:

Edward J. McGrath, Science CoordinatorCarolyn Zogby, Director of InstructionSusan Rash, Director of Curriculum

UNDERSTANDING THE REVISED SCIENCE STANDARDS

There are eight standards in the Delaware Science Content Standards, each clustered for grades K-3, 4-5, 6-8, and 9-12. These clusters are the grade clusters assessed by the Delaware Student Testing Program (DSTP), are similar to the experiences and certification of teachers, and take into account the organization of schools and the frameworks of other content standards.

Standard 1, The Nature and Application of Science and Technology, is the foundational standard on which all others have been developed. This standard emphasizes learning content through inquiry, the interconnectedness of science, technology, and society, and the history and context of science.

The content standards for physical (standards 2 and 3), earth (standards 4 and 5), and life (standards 6, 7, and 8) science focus on big ideas and concepts that are important for all students to know. The eight standards are composed of broad standard statements which communicate the big ideas in the standards.

Each content standard is subdivided into strands with concepts that spiral up through the grade clusters and are written in developmentally appropriate ways guided by current educational research and experience. The big ideas and concepts in each standard are central to science education and focus on depth of concepts rather than breadth of facts or topics. All eight content standards comprise what is to be taught, learned, and assessed. For each strand, there is at least one Enduring Understanding and Essential Question identified. The Standards, Strands, Enduring Understandings, and Essential Questions are the same for all grade level clusters.

Within each grade level cluster, there are substrands which identify the content and/or skills that are addressed for that grade level cluster.

Understanding the coding system for the science standards:

Each of the substrands is identified by a three digit code. The first digit identifies the standard number. The second digit identifies the strand, and the third digit identifies the sub-strand. Please note: when identifying the standards by their three digit code, it is necessary to specify the grade level cluster.

For example, for the 6-8 grade level cluster, standard 2.1.4 refers to

Standard 2: Materials and their PropertiesStrand 1: Properties and Structure of MaterialsSubstrand 4: An important property of materials is their ability to

conduct heat. Some materials, such as certain metals, are excellent conductors of heat while other materials,

such as glass, are poor conductors (good thermal insulators).

UNDERSTANDING THE GRADE LEVEL EXPECTATIONS (GLE) IN SCIENCE

In revising the Delaware Science Content Standards, the Science Design Team has identified a series of Grade Level Expectations (GLEs) for each grade from Kindergarten through twelfth grade. These statements describe activities or performances that are designed to help students meet the standards at each grade level. Although students are tested (through the Delaware Student Testing Program in science) on the Content Standards, the Grade Level Expectations represent a mechanism by which students are expected to meet the standards.

Understanding the coding system for the GLEs:

Each of the GLEs is identified by two numerals (or K) followed by a letter. The first numeral represents the grade (K for Kindergarten). The second numeral represents the standard number as indicated below:

Standard 1: Nature and Application of Science and TechnologyStandard 2: Materials and their PropertiesStandard 3: Energy and its EffectsStandard 4: Earth in SpaceStandard 5: Earth’s Dynamic SystemsStandard 6: Life ProcessesStandard 7: Diversity and Continuity of Living ThingsStandard 8: Ecology

For example, GLE 9.3.u refers to

Grade 9Standard 3 GLE u: Identify that ‘work’ is the process by which a force transfers energy to an object, and use measured quantities to make calculations of the work done by forces (W = energy transferred = F∙D). (3.2.2) (3.3.2)

Each GLE is followed by the Content Standard(s) it supports (see “Understanding the Revised Science Standards).

At the end of the GLE document is a table which summarizes which GLEs support each standard.

SEPTEMBER

Topic 1: Safety

Activities: General safety training—Right-to-Know Law

Assessments: 1. Safety QuizSafety Contract/Contrato de Seguiridad signed by each student

Text References/Vocabulary: noneStandards: noneGLEs: none

Topic 2: Reading in Science/Nature of Science

Standards:

1.1.1: Scientists conduct investigations for a variety of reasons including to explore new phenomena, to replicate other’s results, to test how well a theory predicts, to develop new products, and to compare theories.

1.1.2: Science is distinguished from other ways of knowing by the use of empirical observations, experimental evidence, logical arguments and healthy skepticism.

1.1.3: Theories in science are well-established explanations of natural phenomena that are supported by many confirmed observations and verified hypotheses. The application of theories allows people to make reasonable predictions. Theories may be amended to become more complete with the introduction of new evidence.

1.1.4: Investigating most real-world problems requires building upon previous scientific findings and cooperation among individuals with knowledge and expertise from a variety of scientific fields. The results of scientific studies are considered valid when subjected to critical review where contradictions are resolved and the explanation is confirmed.

1.1.5: Understand that: In communicating and defending the results of scientific inquiry, arguments must be logical and demonstrate connections between natural phenomena, investigations, and the historical body of scientific knowledge.

1.1.6: Knowledge and skills from sources other than science are essential to scientific inquiry. These include mathematics, reading, writing, and technology.

1.2.1: The pursuit of science can generate the need for advanced technology. Advanced technology, in turn, can provide the opportunity to pursue new scientific knowledge.

1.2.2: The social, economic, and political forces of a society have a significant influence on what science and technology programs are pursued, funded, and implemented.

GLEs

10.1.a: Identify and form questions that generate a specific testable hypothesis that guide the design and breadth of the scientific investigation.

10.1.d: Construct logical scientific explanations and present arguments which defend proposed explanations through the use of closely examined evidence.

10.1.e: Communicate and defend the results of scientific investigations using logical arguments and connections with the known body of scientific information.

Assessments:

Current events (see format and rubric)JournalingPersonal glossaryHomework

Text references/vocabulary:

Chapter 2.1 pp. 24-29

data: recorded observations or measurements.

discovery science: a way of learning about the natural world by drawing inferences from observations of natural phenomena and experimentation. Also called inquiry science.

inference: a logical interpretation of observations or other data.

observation: information about natural phenomena obtained by using the senses.

qualitative: a description of data using characteristics, appearances, or properties.

quantitative: a description of data using numbers, proportions, or orders of magnitude.


case study: a detailed description of a real-life situation in discovery science. Case studies may be used to illustrate unifying principles.

control: an experimental treatment which is used as a basis of comparison for other treatments in the same experiment.

hypothesis: a suggested answer to a testable question in science. A hypothesis always includes a rationale for the answer.

if-then reasoning: a type of logical argument in which one situation (the “if” statement) establishes a condition necessary for the second situation (the “then” statement) to occur.

prediction: a statement describing a possible outcome of future events or experimentation.


evidence: collected body of data, measurements, and concrete observations from experimentation.

law: a generalization which describes physical phenomena. A law (also called a principle) is sometimes expressed as a mathematical equation.

model : a physical, mental, or mathematical representation that allows an abstract concept to be perceived in a concrete way.

prove (v) proof (n): to use logical argument to show that a statement is true. (NOTE: it is not always necessary, appropriate, or possible to prove a statement in scientific reasoning. “Prove” should be distinguished from “support with evidence.”)

theory: a well-tested explanation of a group of observations.

Suggested Activities:

Activity 1: What Do You Know—AIDS (Standards 1.1.1, 1.1.2, 1.1.5, 1.2.2. GLE 10.1.a)

GOALS: In this lab activity students will:

Gain information and insight about AIDS from three different sources: personal testimony, newspaper coverage from an AIDS conference, and statistical data from the CDC.

Identify ways that science as a "way of knowing" differs from other "ways." Appreciate that all of these ways of knowing about AIDS are valuable in their own way and none

is more or less worthwhile than the others.

ACTIVITY OVERVIEW: A synopsis of this activity follows:

Students read passages about AIDS from three different sources: selections from the AIDS Memorial Quilt Memory Book Message Board (from contributors who have lost family members to AIDS), from newspaper articles from the Associated Press, and from factual information from the Centers for Disease Control and Prevention. Students evaluate each as a different way of knowing about AIDS and realize that none of these (including the "scientific" way) is more or less valid than the others.

CONTEXT: The concepts that we have been developing and how this activity serves as the next step can be explained as follows:

Students will begin the year with a conception of what science is and what it is not. In middle school, many units focus on the idea of what constitutes a scientific question. In this unit, we ask students to create a definition of science and distinguish science from other ways of knowing about the world (e.g. art, literature, religion).

Activity 2: Solving the Puzzle (Standards 1.1.3, 1.1.4. GLE 10.1.d)


Use a few pieces of a jigsaw puzzle and make inferences about what the entire puzzle looks like. Modify their ideas of what the puzzle looks like based on the appearance of additional pieces

added to the original pieces. Discuss their ideas of what the puzzle is with others in the class. Compare this process to the process of creating and refining scientific theories.


Students work in groups of 4-5. Each group receives an envelope of twenty puzzle pieces (from the same puzzle). The group decides on what the picture on the box might be and sketches their idea. Then, each group receives ten more pieces. They evaluate their idea based on the new pieces of "evidence" and sketch another picture. They receive five more pieces and again re-evaluate their theory of the box cover. Before revealing the actual picture on the box, the groups take a "gallery walk," evaluating other sketches and refining their own theories.


Many students (and adults) have the misconception that a theory is transitory, that it is a "hunch" or a hypothesis. Indeed, one of the major objections many people have to evolution is that it is "only a theory." In this activity, students discover that a theory is an explanation of phenomena. It is based on the evidence at hand, and is revisited whenever new evidence is presented. It is necessary to establish this basis before exploring evolution because students frequently argue that humans have never observed evolution first hand, so it cannot be true.

Activity 3: Scientists in Action (Standards 1.1.1, 1.1.5, 1.1.6, 1.2.1. GLEs 10.1.a, 10.1.e)


Describe the methods and approaches scientists in the field use to answer scientific questions and to explore scientific phenomena.


Students watch two video clips from the PBS Evolution series: "Leaf Cutters of the Amazon" and "Tale of the Peacock." Students identify questions that scientists ask, strategies they use to answer them, and information that drives revision of their theories.


Now that students have an understanding of how science is distinguished from other ways of knowing, students observe actual scientists creating testable questions, conducting research, and revising theories in light of their findings. The subject matter also serves as a foundation for the subsequent material on natural selection.

Topic 3: Evolution by Natural Selection

Standards:

1.1.1: Scientists conduct investigations for a variety of reasons including to explore new phenomena, to replicate other’s results, to test how well a theory predicts, to develop new products, and to compare theories.


1.1.5: Understand that: In communicating and defending the results of scientific inquiry, arguments must be logical and demonstrate connections between natural phenomena, investigations, and the historical body of scientific knowledge.

1.1.6: Knowledge and skills from sources other than science are essential to scientific inquiry. These include mathematics, reading, writing, and technology.

1.3.1: New disciplines of science emerge as older disciplines interface into an integrated study of the natural world. As the body of scientific knowledge grows, the boundaries between individual disciplines diminish.)

7.2.1: Evolution is a change in allelic frequencies of a population over time. The theory of evolution is supported by extensive biochemical, structural, embryological, and fossil evidence.

7.2.3: The process of natural selection occurs when some heritable variations that arise from random mutation and recombination give individuals within a species some survival advantages over others. These offspring with advantageous adaptations are more likely to survive and reproduce, thus increasing the proportion of individuals within a population with advantageous characteristics. When populations become isolated, these changes may accumulate and eventually result in new species.

7.2.6: Genetically diverse populations are more likely to survive changing environments.

GLEs

10.1.a: Identify and form questions that generate a specific testable hypothesis that guide the design and breadth of the scientific investigation.

10.1.b: Design and conduct valid scientific investigations to control all but the testable variable in order to test a specific hypothesis.

10.1.c: Collect accurate and precise data through the selection and use of tools and technologies appropriate to the investigations. Display and organize data through the use of tables, diagrams, graphs, and other organizers that allow analysis and comparison with known information and allow for replication of results.



10.1.f: Use mathematics, reading, writing and technology when conducting scientific inquiries.

10.7.r: Recognize random mutation (changes in DNA) and recombination within gametes as the sources of heritable variations that give individuals within a species survival and reproductive advantage or disadvantage over others in the species.

10.7.s: Analyze natural selection simulations and use data generated from them to describe how environmentally favored traits are perpetuated over generations resulting in species survival, while less favorable traits decrease in frequency or may lead to extinction.

10.7.u: Describe that evolution involves changes in the genetic make-up of whole populations over time, not changes in the genes of an individual organism.

10.7.y: Relate a population’s survival to the reproductive success of adapted individuals in that population.

10.7.z: Explain the roles of geographical isolation and natural selection on the evolution of new species.

10.7.bb: Explain why homogeneous populations may be more vulnerable to environmental changes than heterogeneous populations.

Assessments:

2. Natural Selection Assessment.


Evolution by Natural Selection

Background on Darwin: Chapter 14.1 pp. 292-298

acquired characteristic: a trait of a living organism that was introduced by the environment in which the organism lived.

adaptation: a characteristic of an organism that improves the chances that the organism will survive and/or reproduce in its environment.

evolution: the generation-to-generation changes that occur in species over long periods of time as a result of changes in gene frequency and gene expression from one generation to another.

natural selection: a process by which individuals with variations in characteristics that favor survival tend to leave more offspring capable of reproduction than other individuals with less favorable variations.

Natural Selection: Chapter 14.3 pp. 305-308

finch(es): a small bird found worldwide. The finches of the Galapagos Islands are physically adapted to specific environments.

heritable (inherited) traits: characteristics that are passed from parent to child through genetic inheritance.

population: group of individuals of the same species living in a particular area at the same time.

variation: differences in traits among individuals within a population.


Activity 4: Variation in Peanuts/Variation in Wolves (Standards 1.1.6, 7.2.3, 7.2.5, 7.2.6, GLEs 10.1.f, 10.7.r, 10.7.y, 10.7.z)


Identify variations that exist within populations of plants (peanuts) and animals (wolves) in a given environment.

Recognize trends in quantitative data and identify correlations among these trends. Distinguish between correlations and cause-effect relationships.


Students observe many individual peanut pods (or other plant) that exhibit variations among individuals and make quantitative and/or qualitative data tables. They also review data that shows variation among wolf populations in North America. Students are asked to identify correlations among variations and environments (for example, that white wolves are correlated with the Yukon and rust colored wolves are correlated with Mexico.)


In this first activity in the Natural Selection piece, students are introduced to the important role of variation among individuals in natural selection. Students discuss that all organisms in a population have some sort of variation, even if it is not immediately visible to us. They also learn that in order for variation to contribute to natural selection, it must be passed to offspring--an injury acquired by an organism may affect that organism's survival, but if it is not passed to offspring, it will not affect the species.

Activity 5: A Pepper Explosion (Standards 1.1.6, 7.2.3, 7.2.6, GLEs 10.1.f, 10.7.s, 10.7.y)


Predict the output of green peppers from a single pepper if all the seeds produce one plant. Explain why organisms tend to over-reproduce in their natural environment.


In this activity, students find the mass of a green bell pepper, then cut it open and count its seeds. They calculate the number of peppers and total mass of those peppers assuming each seed produces a plant with twenty peppers. Of course, the number of peppers becomes very large within a few seasons (hence, the "pepper explosion.") Students are asked to relate the need for over-reproduction to competition for resources and the struggle for survival.


This activity introduces the concept of over-reproduction, which, along with heritable variation among species, provides an important component to the theory of evolution by natural selection. Both of these concepts form the basis for the next activity, Survival in the Bean Patch, where natural selection is specifically modeled and analyzed.

Activity 6: Survival in the Bean Patch (Standards 1.1.1, 1.1.3, 1.1.5, 1.1.6, 7.2.1, 7.2.3, 7.2.6GLEs 10.1.a, 10.1.b, 10.1.c, 10.1.d, 10.1.e, 10.1.f, 10.7.r, 10.7.s, 10.7.u, 10.7.y, 10.7.bb)


Conduct a simulation of natural selection in which they predict which individuals in a population are more likely to survive in a given environment and pass their traits on to offspring.

Choose appropriate graphs to display data.


Students observe five types of dried beans that differ only in color, and make predictions about which will be most likely to avoid capture in a given environment (a ring of approximately 1.5 square meters on the school grounds). Students also simulate reproduction of "survivors" to determine the distribution of beans in subsequent generations. This activity is linked to SchoolNet.


This activity brings together the concepts developed in the previous two activities as a full simulation of natural selection. It illustrates the importance of the struggle for survival as well as the importance of passing favorable traits on to offspring through reproduction. The next unit asks the question, "what evidence is there that this happens and is responsible for the diversity of species on Earth today?"

SCIENCE SAFETY QUIZ

Write your responses in the boxes provided.

1. When should we wear goggles in the lab?

2. What information is contained on a label?

3. What is an unauthorized experiment? Why is it not permitted?

4. When heating water on a hot plate, everyone in lab should wear goggles. List two other safety rules to follow when heating a beaker of water on a hot plate.

5. .When you heat a test tube over an open flame, you should always wear goggles. List two other safety rules to follow when heating a test tube over an open flame.

SCIENCE SAFETY QUIZ--RUBRIC

Write your responses in the boxes provided. (two points each.) NOTE: there are no criteria for a partial response (1). Each question is scored as a complete response (2) or an incorrect response (0)

1. When should we wear goggles in the lab?

2. What information is always contained on a label?

3. What is an unauthorized experiment? Why is it not permitted?

Whenever we work with chemicals, with heat, with glassware, or with any

danger from flying projectiles.

The label contains the name of the chemical, date of preparation, and

hazard information. Solutions also contain the concentration.

An unauthorized experiment is one that is not part of the assignment which student performs without first informing the teacher. Unauthorized experiments often produce hazardous conditions that students may not have anticipated. Because the teacher is not involved with their design, the teacher may have difficulty dealing with these hazards. Therefore, unauthorized experiments are forbidden.

4. When heating water on a hot plate, everyone in lab should wear goggles. List two other safety rules to follow when heating a beaker of water on a hot plate.

5. .When you heat a test tube over an open flame, you should always wear goggles. List two other safety rules to follow when heating a test tube over an open flame.

Do not touch glass with bare hands. Use tongs or other protective devices.

Keep area around hot plate free of clutter. Before heating, be sure beaker is free of cracks. No horseplay around hot plate.(any two are required for a complete response)

Shoulder length hair is tied back. Point opening of test tube away from other people. Test tube must be no more than ¼ full of any chemical. Use test tube holder (tongs) to hold test tube, not bare hands.(any two are required for a complete response)

Natural Selection Assessment

Introduction

In 1973, biologists Peter and Rosemary Grant began a 20-year long study to find out if they could document natural selection. On Daphne Major, a tiny island in the Galapagos, they recorded the lengths, the masses, and the diets of hundreds of ground finches (tiny birds about the size of sparrows). The diet of ground finches consists mostly of seeds.

Among ground finches, coloration, body size, wing length and the size and length and depth of the beak are inherited traits that vary in the population. The Grants found that finches with large beak depths also have big bodies. Finch beak depth is illustrated below:

In 1977 a severe drought occurred on Daphne Major. Plants withered and seeds of all kinds were scarce. Small soft seeds were quickly eaten by the finches, leaving mainly large, tough seeds that finches normally ignore. The drought ended when a small amount of rain fell on the island in January of 1978.

Beak Depth

Ground Finch

Figures 1, 2, 3, and 4 on the next two pages illustrate data collected by the Grants on Daphne Major.

1976 Finch Population Beak Depth (Total Number in Sample = 751)

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Changes in Finch Population Before and After the Drought of 1977

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Use Information in the Introduction and Figures 1-4 in answering the following questions:

1. What do the data in Figure 1 indicate about the range in beak depth in the finch population in 1976? (Note: Use numerical data in your response.)

2. How does mean beak depth before the drought (Figure 1) compare with mean beak depth after the drought (Figure 2)? (Note: Use numerical data in your response.)

Changes in Seed Abundance Before and After the Drought of 1977

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3. Propose an explanation that accounts for the change in the mean depth of the finches’ beaks between 1976 and 1978 using your knowledge of natural selection, and the information in the Introduction and Figures 1-4.

Rubric--Natural Selection Assessment

1. What do the data in Figure 1 indicate about the range in beak depth in the finch population in 1976? (Note: Use numerical data in your response.)

Criteria for a complete response (2):

Student responds with a statement that includes a numerical description of the range in beak depth. For example:

The finch beak depth variation ranged from 5.8-mm to 13.8-mm. Most of the finches had beak depths that ranged from about 8-mm to 11-mm.

Criteria for a partial response (1):

Gives the correct mean beak depth (9.2-mm) but does not include range or

uses correct numerical values (half the population has beak depths that range between 5.8-mm and 9.2-mm) that give an incomplete description of the range of beak depth or

correct numerical values listed but not described.

Criteria for an incorrect response (0):

Student indicates no variation in range or

Student gives a correct non-numerical description of range; i.e. beak depth varies from small to large or

Student uses incorrect numerical values or

Student misinterprets graph axes.

2. How does mean beak depth before the drought (Figure 1) compare with mean beak depth after the drought (Figure 2)? (Note: Use numerical data in your response.)


Student compares the numerical values for mean beak depth before and after the drought. For example:

Mean beak depth increased from 9.2-mm to 10.0-mm. Mean beak depth increased 0.8-mm.


Uses one correct and one incorrect numerical value in comparing means


Uses incorrect numbers to compare means or describe increase in mean or

Indicates that beak depth did not change or that it decreased or

Indicates beak depth mean increased but uses no numerical data or

Responds by describing population change, not mean beak depth change.

3. Propose an explanation that accounts for the change in the mean depth of the finches’ beaks between 1976 and 1978 using your knowledge of natural selection, and the information in the Introduction and Figures 1-4.


The student responds by including the following requirements in an explanation or hypothesis that accounts for the change in finch mean beak depth:

a. Variation: Genetic variation is present among members of a population. population.

b. Struggle for survival: The survival of an individual organism depends on its ability to compete successfully for food and other resources and to avoid predation and disease.

c. Differential survival and reproduction: Individuals with the most successful adaptations to their environment are most likely to survive and reproduce. Over generations the character of a population changes as the frequency of a trait increases or decreases.


The student response includes any two of these requirements in the explanation.

Criteria for an incomplete response (0):

The student response includes less than two of these requirements in the explanation or

the explanation reflects Lamarckian theory (i.e. an explanation based on use and/or disuse of structures and inheritance of acquired characteristics).

OCTOBER

Topic 4: Evidence for Evolution

Standards:



1.1.5: In communicating and defending the results of scientific inquiry, arguments must be logical and demonstrate connections between natural phenomena, investigations, and the historical body of scientific knowledge.

7.2.1: Evolution is a change in allelic frequencies of a population over time. The theory of evolution is supported by extensive biochemical, structural, embryological, and fossil evidence.

7.2.2: The great diversity of organisms is the result of more than 3.5 billion years of evolution that has filled every available niche with life forms. The millions of different species of plants, animals, and microorganisms that live on Earth today are related by descent with modification from common ancestors.

7.2.4: Evolution does not proceed at the same rate in all populations; nor does it progress in a linear or set direction. Environmental changes have a strong influence on the evolutionary process. Other factors that influence evolution include: sexual selection, mutation, genetic drift, and genetic modification.

7.2.5: Organisms are classified into a hierarchy of groups and subgroups based on similarities in structure, comparisons in DNA and protein and evolutionary relationships. 7.3.3: DNA is analyzed to determine evolutionary relationships, study populations, identify individuals, and diagnose genetic disorders.

7.3.3: DNA is analyzed to determine evolutionary relationships, study populations, identify individuals, and diagnose genetic disorders.

GLEs




10.1.f: Use mathematics, reading, writing and technology when conducting scientific inquiries.

10.7.t: Explain how biochemical evidence, homologous structures, embryological development and fossil evidence support or refute prior hypotheses of common ancestry.

10.7.v: Explain how species evolve through descent with modification, thus allowing them to adapt to different environments.

10.7.y: Relate a population’s survival to the reproductive success of adapted individuals in that population.


10.7.cc: Explain how evolutionary relationships between species are used to group organisms together.

Assessments:

3. Chicken Wings and Batter’s Arms Assessment.


Evidence for Evolution

Chapter 14.2 pp. 299-304

development: a series of predictable changes that occur in an organism during the life cycle.

embryonic features: characteristics that appear in immature forms of an organism.

fossil record: a collection of remains of ancient organisms that are preserved in sedimentary rock layers.

homologous structure: a structure that appears in several distantly related organisms. Homologous structures have similar components and give evidence of a common ancestor.

vestigial structure: a structure in an organism that appears to have no discernable function but may have had a function in the organism’s evolutionary ancestors.

(note: evidence from molecular biology will be addressed during the genetics unit in March)


Activity 7: Chicken Wings and Batter's Arms (Standards 7.2.1, 7.2.2, 7.2.4, 7.2.5GLEs 10.7.t, 10.7.v, 10.7.y, 10.7.z, 10.7.cc)


Relate the bones of forelimbs in vertebrates to evolutionary relatedness. Recognize that evolution occurs to species, not individuals. Appreciate the amount of time (~ 3.5 billion years) life has evolved on Earth


Students observe the bones in a chicken wing (cooked) and compare them to the bones in the forearms of other vertebrates. Students explore the idea that homologous bones are present in the representative vertebrates, but they perform different functions in each. One explanation for this finding is that all of the organisms studied (including humans) evolved from a common ancestor with these same bones. As the descendants of this ancestor passed heritable variations to offspring, those offspring were able to survive in different environments as a result of these variations.


In this activity, evidence in support of evolution is presented. The first line of evidence we present is the presence of homologous structures in living things. In sixth grade (Earth History), students use sedimentary rock layers to make inferences about geological history--"the present is the key to the past" is what they're told. This activity applies that same logic to evolutionary theory. This activity might also lead to discussion about embryological evidence for evolution, that in some cases, the embryos of living organisms resemble the evolutionary ancestors of those organisms.

Activity 8: The Whale's Tale (Standards 1.1.3, 1.1.4, 1.1.5, 7.2.1, 7.2.2, 7.2.5, 7.3.3, GLEs 10.1.d, 10.1.e, 10.7.t, 10.7.u, 10.7.v, 10.7.cc)


Critique an evolutionary theory in light of new evidence. Re-create the process of developing a cohesive theory about whale evolution from land mammals

by piecing together fossil evidence.

ACTIVITY OVERVIEW: a synopsis of this activity follows:

Students use evidence from the anatomy of modern whales and fossil discoveries to draw tentative explanations about whale ancestry. Students view a CD PowerPoint "Evolution of Whales" and the PBS Teaching and Learning video "How Do We Know Evolution Really Happens?" segment 3.


This activity re-visits the idea of a theory and illustrates how and why a theory might be revised. This activity may also serve as an introduction to the concept of genetic evidence as a key to evolutionary relationships.

Activity 9: Hominid Skull Comparisons (Standards 1.1.3, 1.1.4, 1.1.6, 7.2.1, 7.2.2GLEs 10.1.c, 10.1.d, 10.1.f, 10.7.v, 10.7.cc)


examine skull casts from primates and ancestral hominids to evaluate evolutionary relationships between living and extinct primates.

decide if humans are the product of evolution based on evidence from the fossil record.


Students begin by expressing their opinions about the evolutionary origins of humans in a journal entry. Then, they collect data from seven hominoid skull casts, comparing features on the casts of extinct hominids (Australopithecus afarensis, Australopithecus boisei, Homo erectus, Homo neandertalis) to those of modern primate skull casts (human, gorilla, chimpanzee).


In this activity, the question of how do humans fit into the evolution equation is addressed. Students observe that human skulls and gorilla skulls have many homologous structures (e.g. eyes in front of the skull, presence of molars and canine teeth). By comparing various homologous structures on extinct hominids to those on human, chimpanzee, and gorilla, students begin to make hypotheses about when various hominids lived.

Topic 5: Evolutionary Mechanisms

Standards:


: 7.2.1: Evolution is a change in allelic frequencies of a population over time. The theory of evolution is

supported by extensive biochemical, structural, embryological, and fossil evidence.

7.2.3: The process of natural selection occurs when some heritable variations that arise from random mutation and recombination give individuals within a species some survival advantages over others. These offspring with advantageous adaptations are more likely to survive and reproduce, thus increasing the proportion of individuals within a population with advantageous characteristics. When populations become isolated, these changes may accumulate and eventually result in new species.

7.2.4: Evolution does not proceed at the same rate in all populations; nor does it progress in a linear or set direction. Environmental changes have a strong influence on the evolutionary process. Other factors that influence evolution include: sexual selection, mutation, genetic drift, and genetic modification.

GLEs

10.7.w: Discuss how environmental pressure, genetic drift, mutation and competition for resources influence the evolutionary process. Recognize that a change in a species over time does not follow a set pattern or timeline


10.7.aa: Predict possible evolutionary implications for a population due to environmental changes over time (e.g., volcanic eruptions, global climate change, and industrial pollution).

Assessments

4. Evolutionary mechanisms assessment.5. Microevolution assessment


Evolutionary Mechanisms

Chapter 14.4 pp. 310-316 (Honors level only: Online resources Chapter 14.4 Closer Look)

allele: alternate form of a gene which may result in a predictable phenotype.

founder effect: a mechanism of genetic drift where a few organisms from a population colonize a new environment. These organisms (the “founders”) may not represent the original population. As a result, assuming the founders are able to survive and pass their genetic material to offspring, a new population with traits common to the founders appears.

gene: a unit of inherited information in DNA.

gene pool: all of the alleles from all of the individuals that make up a population.

genetic drift: change in the gene pool of a population due to random variation or random migration.

mutation: a change in the nucleotide sequence in a strand of DNA.

(Honors level only)

Hardy-Weinberg Equilibrium: a steady state condition that occurs in a population when the allelic frequency in the gene pool remains the same over time.


Specific lab activities have not been developed for this unit. To illustrate genetic drift by reproductive isolation, Activity 6 (Survival in the Bean Patch) can be modified in the following way:

1. Partition off part of the ring where the beans are fist distributed. Count the beans in the partition (see diagram below)

2. Have students count beans in smaller area and in larger area.3. Calculate the percentage of each bean in each area (sample data is given below)

bean color number of beans in small area percentage of beans in small areabrown 3 30

red 4 40white 0 0black 2 20pinto 1 10

bean color number of beans in large area percentage of beans in large areabrown 17 19

red 16 18white 20 22black 18 20pinto 19 21

4. Using the percentage of beans in small area, count out that number of beans and run the simulation. Compare data to what was obtained in the original activity.

5. Ask students how geographic isolation affects the results.

CHICKEN WINGS AND BATTERS’ ARMS

(NOTE: Please refer to Vertebrate Forelimb Homologies Chart

1. A human hand (and foot) has five digits (fingers or toes). There is nothing magical about having five digits at the end of your limbs, but five is the pattern that runs through all animals with four limbs. Even when there are fewer than five digits in some adult animals (such as horses and birds) it turns out that they have five digits as embryos. What could account for these animals having such similar bone structures in their forelimbs?

2. Structures such as butterfly wings and bird wings are called analogous structures. They have similar appearance and function, but they are not the result of shared ancestry. Does the presence of analogous structures in different species indicate a close evolutionary relationship? Explain.

3. Why does the presence of homologous structures provide important evidence for showing evolutionary relationships?

RUBRIC--CHICKEN WINGS AND BATTERS’ ARMS ASSESSMENT

1. A human hand (and foot) has five digits (fingers or toes). There is nothing magical about having five digits at the end of your limbs, but five is the pattern that runs through all animals with four limbs. Even when there are fewer than five digits in some adult animals (such as horses and birds) it turns out that they have five digits as embryos. What could account for these animals having such similar bone structures in their forelimbs?


Student states that these animals have a common ancestor with five digits at the end of its limbs.


Student states that these animals have a common ancestor but does not indicate that the ancestor had five toes.


Student states that one modern animal evolved from another modern animal or other incorrect explanation.

2. Structures such as butterfly wings and bird wings are called analogous structures. They have similar appearance and function, but they are not the result of shared ancestry. Does the presence of analogous structures in different species indicate a close evolutionary relationship? Explain.


Student states that analogous structures do not indicate a close evolutionary relationship because although the structures perform similar functions, they have very different structures, therefore different evolutionary origins.


Student states that analogous structures do not indicate a close evolutionary relationship but give no explanation, an incorrect explanation, or an unclear explanation of why.


Student states that analogous structures may indicate a close evolutionary relationship, with or without an explanation.

3. Why does the presence of homologous structures provide important evidence in support of the theory of evolutionary relationships?


Student states that if different organisms possess similar structures with different functions (homologous structures), the most likely explanation is that they had a common ancestor with these structures, and modifications of these structures allowed the descendents to adapt to different environments.


Student describes homologous structures correctly, but does not explain their link to evolutionary relationships.


Student states that homologous structures do not provide evidence in support of the theory of evolutionary relationships or student gives an incorrect or incomplete description of homologous structures.

NOTE: If student has met the criteria for a complete response but also states a disbelief of evolutionary theory, response should be scored as a complete response (2).

EVOLUTIONARY MECHANISMS

1. Little rain fell on Daphne Major from 1979 through 1982. At the beginning of 1983 unusually heavy rainfall occurred on the island. Plants that produced small seeds flourished while big-seed plant populations dropped sharply. With plenty of food available, the size of the finch population increased dramatically over the next several years.

a. Predict how the rainy weather of 1983 affected mean (average) beak depth over the next several generations using your knowledge of natural selection. Make your prediction by circling one of the following choices:

A. Mean (average) beak depth increased.B. Mean (average) beak depth decreased.C. Mean (average) beak depth remained the same.

b. Explain your prediction.

Natural Selection Assessment

Introduction

In 1973, biologists Peter and Rosemary Grant began a 20-year long study to find out if they could document natural selection. On Daphne Major, a tiny island in the Galapagos, they recorded the lengths, the masses, and the diets of hundreds of ground finches (tiny birds about the size of sparrows). The diet of ground finches consists mostly of seeds.

Among ground finches, coloration, body size, wing length and the size and length and depth of the beak are inherited traits that vary in the population. The Grants found that finches with large beak depths also have big bodies. Finch beak depth is illustrated below:

In 1977 a severe drought occurred on Daphne Major. Plants withered and seeds of all kinds were scarce. Small soft seeds were quickly eaten by the finches, leaving mainly large, tough seeds that finches normally ignore. The drought ended when a small amount of rain fell on the island in January of 1978.

Beak Depth

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Figures 1, 2, 3, and 4 on the next two pages illustrate data collected by the Grants on Daphne Major.


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Changes in Seed Abundance Before and After the Drought of 1977

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RUBRIC FOR ASSESSMENT 4 EVOLUTIONARY MECHANISMS

Little rain fell on Daphne Major from 1979 through 1982. At the beginning of 1983 unusually heavy rainfall occurred on the island. Plants that produced small seeds flourished while big-seed plant populations dropped sharply. With plenty of food available, the size of the finch population increased dramatically over the next several years.

a. Predict how the rainy weather of 1983 affected mean (average) beak depth over the next several generations using your knowledge of natural selection. Make your prediction by circling one of the following choices:

D. Mean (average) beak depth increased.E. Mean (average) beak depth decreased.F. Mean (average) beak depth remained the same.

b. Explain your prediction.


Student chooses B, and explains using the following points:

In the new environment the trait for small beak depth enables finches to compete and survivemore successfully than finches with large beaks.

Over generations differential survival and reproduction of individual finches with the variation for small beak depth results in a decrease in mean beak depth.


Student chooses B, and includes only one of the two points listed above.


Student chooses B but provides no explanation, an incorrect explanation (i.e. a Lamarckian explanation) or an incomplete explanation (e.g. “struggle for survival,” “small beaks evolved”) or

Student chooses A or C, with or without an explanation.

MICROEVOLUTION IS A CHANGE IN A POPULATION’S GENE POOL

Adapted from Activity 14.4 of Online Activities Biology—Exploring Life

Microevolution is a term that describes the change in the frequencies of alleles in a population from generation to generation. Remember that only the alleles of organisms that reproduce successfully in one generation appear in the gene pool of the next generation.

1. Which one of these four causes of microevolution (genetic drift, genetic flow, mate selection, natural selection) is most likely to lead to adaptation? Explain.

2. Compared to genetic drift, how might gene flow change the allele frequency in a population?

ASSESSMENT—MICROEVOLUTION IS A CHANGE IN A POPULATION’S GENE POOL

Adapted from Activity 14.4 of Online Activities Biology—Exploring Life

Microevolution is a term that describes the change in the frequencies of alleles in a population from generation to generation. Remember that only the alleles of organisms that reproduce successfully in one generation appear in the gene pool of the next generation.

1. Which one of these three causes of microevolution (genetic drift, genetic flow, natural selection) is most likely to lead to adaptation? Explain.

2. Compared to genetic drift, how might gene flow change the allele frequency in a population?

Complete response (2): Natural selection is most likely to lead to adaptation. Genetic drift and gene flow cause changes in allelic frequencies through random occurrence. Natural selection changes allelic frequencies when variations within a population increase the likelihood of survival and/or reproduction.

Partial response (1): Response chooses natural selection and describes the randomness associated with genetic drift and gene flow but does not explain that natural selection increases likelihood of survival or reproduction.

Incorrect/incomplete response (0): Response chooses natural selection but gives no rationale or chooses one of the other two causes with or without rationale.

Complete response (2): In gene flow, individuals enter or leave a population, thus changing the allelic frequency by a known amount. Genetic drift causes random changes in allelic frequency. These changes cannot be predicted.

Partial response (1): Either gene flow or genetic drift is accurately explained as above but not both processes.

Incorrect response (0): Question is not answered or both processes are explained incorrectly or the correct answers for each are given but are reversed (i.e. the response for gene flow is given as the description of genetic drift and vice-versa)

NOVEMBER

Topic 6: Why Evolution Matters Now

Standards:

1.1.1. Scientists conduct investigations for a variety of reasons including to explore new phenomena, to replicate other’s results, to test how well a theory predicts, to develop new products, and to compare theories.


1.1.5: In communicating and defending the results of scientific inquiry, arguments must be logical and demonstrate connections between natural phenomena, investigations, and the historical body of scientific knowledge.

1.1.6: Knowledge and skill from sources other than science are essential to scientific inquiry. These include mathematics, reading, writing, and technology.

1.3.1: New disciplines of science emerge as older disciplines interface into an integrated study of the natural world. As the body of scientific knowledge grows, the boundaries between individual disciplines diminish

6.1.2: Cells take highly varied forms in different plants, animals, and microorganisms. Structural variations among cells determine the function each cell performs.

7.2.1. Evolution is a change in allelic frequencies of a population over time. The theory of evolution is supported by extensive biochemical, structural, embryological, and fossil evidence.

7.2.4. Evolution does not proceed at the same rate in all populations; nor does it progress in a linear or set direction. Environmental changes have a strong influence on the evolutionary process. Other factors that influence evolution include: sexual selection, mutation, genetic drift, and genetic modification.

7.2.6. Genetically diverse populations are more likely to survive changing environments.

7.2.7. Biological evolution is the foundation for modern biology and is used to make predictions for medical, environmental, agricultural and other societal purposes.

8.3.5. People manage the Earth and its resources by preservation, conservation, appropriate utilization, and restoration. The complexity and interaction of these ecosystems requires individual and collaborative efforts on a local, regional, national, and international scale.

GLEs

10.1.b: Design and conduct valid scientific investigations to control all but the testable variable in order to test a specific hypothesis.




10.7.s: Analyze natural selection simulations and use data generated from them to describe how environmentally favored traits are perpetuated over generations resulting in species survival, while less favorable traits decrease in frequency or may lead to extinction.

10.7.v: Explain how species evolve through descent with modification, thus allowing them to adapt to different environments.

10.7.w: Discuss how environmental pressure, genetic drift, mutation and competition for resources influence the evolutionary process. Recognize that a change in a species over time does not follow a set pattern or timeline.

10.7.bb: Explain why homogeneous populations may be more vulnerable to environmental changes than heterogeneous populations.

10.7.dd: Explain how antibiotic resistance populations evolve from common bacterial populations

Assessments:

6. State Assessment: “Why Evolution Matters Now”


Why Evolution Matters Now

Chapter 14.3 (end) pp. 307-308Chapter 14.5 pp. 318-319

Key terms:

antibiotic: a chemical substance excreted by one organism that exerts a specific inhibitory or killing effect on a micro-organism.

bacteria: single celled organism of the kingdom Monera that lacks a membrane bound nucleus and membrane bound organelles. Bacteria carry out all the functions of life.

pesticide: a chemical made to kill insects or other arthropods.

resistance (to pesticides, antibiotics): a condition in targeted organisms in which the organisms are not harmed by chemical substances that might otherwise be harmful. Resistance of this sort is sometimes the result of inherited genes.


Activity 9: Bacterial Growth Experiment(Standards 1.1.1, 1.1.4, 1.1.5, 1.1.6, 1.3.1, 6.1.2, 7.2.1, 7.2.4, 7.2.6, 7.2.7, 8.3.5GLEs 10.1.b, 10.1.c, 10.1.d, 10.1.e, 10.7.s, 10.7.v, 10.7.w, 10.7.bb, 10.7.dd)


Use aseptic technique to culture bacteria on agar and identify antibiotic resistant strain. Relate natural selection to the emergence of drug resistance in bacteria (or viruses, weeds, or

insects) Develop an understanding of infectious disease and identify practices that may decrease the risk

of spreading infectious disease by resistant micro-organisms.


In this laboratory activity students investigate resistance of the bacterium Pseudomonas fluorescens to the antibiotic kanamycin. Students transfer an exponential phase broth culture to agar plates that either contain kanamycin or don’t contain kanamycin (growth only occurs on plates that lack the drug at first. This establishes sensitivity). Then, the broth culture is sub-cultured to broth containing low levels of kanamycin. A week later, the subculture is also transferred to plates with and without the antibiotic. Students draw conclusions about why colonies form on the kanamycin plate.


This activity does many things. Students learned about bacteria in seventh grade during Diversity of Life. The idea of bacteria as agents of infectious disease is introduced, and elaborated further in Chemical Biology. This subunit is important because students frequently reach this part of the study of evolution believing it is a phenomenon that only affected our evolutionary ancestors millions of years ago. In fact, evolution not only affects organisms today, but the problem of drug resistance is one of great concern in medicine and environmental science.

WHY EVOLUTION MATTERS NOW

1. Two weeks ago, Lulu-Anne was diagnosed with strep throat which is caused by the bacterium Streptococcus pyogenes. She was treated by her family doctor with the antibiotic called amoxicillin. Soon after finishing all the doses of amoxicillin in her prescription, she felt better and most of symptoms of the infection had disappeared.

However, when she woke up in the morning a few days later, her throat was sore and her tonsils and the back of her throat were red, swollen, and dotted with white specks of pus. She also experienced chills, body aches and a fever of 102 degrees Fahrenheit. Her mother suspected that Lulu-Anne probably had strep throat again because these symptoms matched those her daughter experienced before taking the amoxicillin.

In a follow-up visit to the doctor it was discovered that indeed, Lulu-Anne was suffering from a recurrence of the Streptococcus pyogenes infection. The doctor prescribed the same dosage and number of treatments of amoxicillin as was done for her first strep infection. However, this second amoxicillin treatment was ineffective. After taking all the antibiotic in her prescription Lulu-Anne continued to have a sore throat, fever, and other symptoms of a strep infection.

Explain why the second round of antibiotic treatment did not control the strep infection by using your knowledge of natural selection.

2. In a laboratory experiment a small sample of the bacterium Streptococcus pyogenes and some nutrient broth were placed on a microscope slide. Bacteria cells present on the slide were observed and counted every 24 minutes for a total of 144 minutes. Ninety-six minutes after the experiment began the antibiotic amoxicillin was added to the bacteria growing on the slide. The following drawings illustrate microscopic views of the bacteria. The label below each drawing shows time (t) in minutes (min) and the number of bacteria (n) present on the slide.

2a. Construct a connected line graph that illustrates changes in the bacteria population using data from the labeled drawings Plot time on the X axis and the number of bacteria on the Y axis. Be sure to include a title and label all axes with correct units.

t = 0 min, n = 2 t = 24 min, n = 4 t = 48 min, n = 8 t = 72 min, n = 16

t = 96 min, n = 32 t = 120 min, n = 10 t = 144 min, n = 20

2b. Describe what happened to the size of the bacteria population after the antibiotic was added.

2c. Sometimes doctors treat a patient with particular bacterial infection with several different antibiotics simultaneously. This treatment is known as a “multi-drug cocktail”.

1). What do you predict will happen to the bacteria population if a multi-drug cocktail is added (instead of amoxicillin) at 96 minutes?

2). Explain your prediction.

3a. Select the graph which best represents the size of the bacterial population from t=0 to t=144 minutes, assuming the multi-drug cocktail was given at 96 minutes.

A.

B.

C.

D.

3b. Explain why you selected the graph that you did.

Bacterial Growth

Bacterial Growth

Bacterial Growth

Bacterial Growth

Rubric for Assessment 6 Why Evolution Matters Now

1. Explain why the second round of antibiotic treatment did not control the strep infection by using your knowledge of natural selection.


Student responses must include

a. Prior to being exposed to amoxicillin, one or more of the bacterial organisms in Lulu-Anne’s body had a genetic variation for resistance to amoxicillin.

b. After the first round of amoxicillin treatment, bacteria with the resistant trait survived while those without the resistant trait died.

c. The bacteria with the amoxicillin resistant trait reproduced and passed the trait for resistance to their offspring. The amoxicillin resistant offspring were not controlled by the second round of treatment with amoxicillin.


Student response includes two of the criteria for a complete response.


Student response includes fewer than two of the criteria for a complete response.

2c. Sometimes doctors treat patients with a particular bacterial infection with several different antibiotics simultaneously. This treatment is known as a “multi-drug cocktail”.

What do you predict will happen to the bacteria population if a multi-drug cocktail is added (instead of amoxicillin) at 96 minutes? Explain.

Criterion for a complete response (2):

a. Students respond by indicating that the bacterial population would be expected to drop to zero or at least a population number lower than the reduction caused by the ampxicilliin treatment.

b. Students respond with a statement indicating that a multi-drug cocktail contains antibiotics that attack bacteria in different ways, and a bacterial population that has evolved resistance to one antibiotic is unlikely to have evolved resistance to all the antibiotics in a multi-drug cocktail.


Students respond by stating that the bacterial population would be expected to drop to zero or at least a population number lower than the reduction caused by the ampxicilliin treatment but do not explain why.


Student states that the population would increase or remain the same with or without an explanation.

3. b. Criteria for a complete response (2):

Student chooses graph A, explaining that this graph shows an increase in bacteria until the time when the multi-drug cocktail is given (96 minutes). From that point on, the bacterial population decreases.


Student chooses graph A but gives no explanation or gives an incorrect explanation or gives an irrelevant explanation.


Student chooses a graph other than A, with or without an explanation.

DECEMBER

Topic 7: Infection and Immunity

Standards:

6.1.2. Cells take highly varied forms in different plants, animals, and microorganisms. Structural variations among cells determine the function each cell performs.

6.1.4. The cell membrane is dynamic and interacts with internal membranous structures as materials are transported into and out of the cell.

6.1.8. In multi-cellular organisms, cells perform specialized functions as parts of sub-systems (e.g., tissues, organs, and organ systems), which work together to maintain optimum conditions for the benefit of the whole organism.

6.1.10. The immune system consists of cells, organs, and secretions that protect the organism from toxins, irritants, and pathogens.

6.3.1. The endocrine, nervous, and immune systems coordinate and help maintain homeostasis in humans and other organisms.

GLEs:

10.6.j: Recognize that as a result of the coordinated structures and functions of organ systems, the internal environment of the human body remains relatively stable despite changes in the outside environment.

10.6.k: Explain how the cells of a multi-cellular organisms work together for the benefit of the colonial or singular organism.

10.6.dd: Recognize that in order to help maintain the health of an organism, the immune system works in nonspecific ways (e.g., skin, mucous membranes) and specific ways (e.g., antibody-antigen interactions.)

Assessment:

7. Search and Destroy, questions 1-3.

Text references/vocab:

Infection and Immunity

Chapter 16.4 pp. 369-370Chapter 16.5 p. 372 (introduction only) p. 375

hygiene: practices associated with ensuring good health and cleanliness.

immune system: a collection of mechanisms within an organism that protects against infection by identifying and killing pathogens.

infection: harmful colonization of a host organism by a foreign species.

mucous lining: The moist external lining of some animal body parts (e.g. mouth, urogenital tract) that secretes a slippery substance (mucus), providing a physical barrier to certain invading pathogens.

pathogen: a biological agent that causes illness to its host.

vaccine: an antigenic preparation (either killed pathogens, non-infectious micro-organisms, or suspensions of biological molecules) used to establish specific immunity to a disease in an animal.

virus: a microscopic particle (ranging in size from 20 - 300 nm) that can infect the cells of a biological organism. Viruses are not cells, and can replicate themselves only by infecting a host cell.

Honors level: Chapter 16.5 pp. 372-375

lysogenic phase: a deviation from the lytic cycle of viral replication in which viral DNA (or cDNA in the case of RNA viruses) integrates with the host DNA.

lytic cycle: the main method of viral replication characterized by penetrationof the host by viral genetic material, synthesis of viral particles, and release of viral particles.

phage (or bacteriophage): a bacterial virus. (NOTE: the two terms are used interchangably).

Chapter 31.1-31.3 pp. 676-683

antibody: a large protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses.

antigen: a molecule that stimulates an immune response.

infectious disease: an illness of humans or animals that results from the presence and activity of one or more pathogenic agents.

nonspecific defense : An immune response present in animals and plants that protects the host from all invading pathogens without providing lasting recognition of the pathogens. Nonspecific defenses include surface protection (e.g. waxy cuticle on leaves, skin on animals) and innate immunity (e.g. inflammation).

transmission (of disease): the mechanism by which a disease passes from one victim to another.

http://en.wikipedia.org/wiki/Nano


Activity 19: "Search and Destroy" GOALS: In this lab activity, students will

Learn about nonspecific and specific immune responses in the human body, including the interaction between antigens and antibodies.

Explain how molecular shape and charge allow specific molecular interactions.

Interpret how scientists use molecular models to design therapeutic drugs.

ACTIVITY OVERVIEW: A synopsis of this lesson follows: This activity is designed to help students understand the importance of molecular shape and charge in molecular-recognition, and to understand the importance of molecular recognition to immune-system function. Students begin the activity by exploring the nonspecific response of the immune system. A progression is made from the nonspecific response to the specific response of the immune system. In addition, the activity gives students hands-on experience in three-dimensional model building. It also provides an excellent opportunity to review the structure of cell membranes.

CONTEXT: The concepts that we have been developing and how this activity serves as the ‘next step’ can be explained as follows Students have explored the basic anatomy and physiology several body systems, and how coordination and response is vital to the survival of a multicellular organism. This activity focuses on the immune system. The immune system is always prepared for invasions by bacteria, viruses and other microorganisms. There are two defense systems that work alone yet together. The specific and nonspecific defense systems work together to protect the body. In most cases, our nonspecific defenses alone are enough to keep out pathogens and ward off infection. In others, the specific defense system must be activated to reinforce and enhance the nonspecific mechanisms. This activity further explores how the specific defense system works.

Topic 8: Molecules of Life

Standards:

2.1.2 Elements and compounds are pure substances. Elements cannot be decomposed into simpler materials by chemical reactions. Elements can react to form compounds. Elements and/or compounds may also be physically combined to form mixtures.

2.3.1: The total mass of the system remains the same regardless of how atoms and molecules in a closed system interact with one another, or how they combine or break apart.

2.4.6: Certain small molecules (monomers) react with one another in repetitive fashion (polymerization) to form long chain macromolecules (polymers). The properties of the macromolecules depend on the properties of the molecules used in their formation and on the lengths and structure of the polymer chain. Polymers can be natural or synthetic.

6.2.1: Cells carry out a variety of chemical transformations (i.e., cellular respiration, photosynthesis, and digestion) which allow conversion of energy from one form to another, the breakdown of molecules into smaller units, and the building of larger molecules from smaller ones. Most of these transformations are made possible by protein catalysts called enzymes.

GLEs:

10.6.l: Use molecular models to explain how carbon atoms uniquely bond to one another to form a large variety of molecules, including those necessary for life (e.g., polysaccharides, polypeptides).

10.6.m: Observe formulas and diagrams of compounds found in food (fats, proteins, carbohydrates). Identify elements that comprise these compounds.

10.6.r: Describe the process by which water is removed from sugar molecules (dehydration synthesis) to form carbohydrates and is added to break them down (hydrolysis).

10.6.t: Identify the reactants and the products in equations that represent photosynthesis and cellular respiration. Explain how the equations demonstrate the Law of Conservation of Matter and Energy in terms of balanced equations.

Assessment:

8. McMush—writing prompt.


(NOTE: Chapter 4 may be used as review of Foundations of Chemistry if needed)

Carbon chemistry: Chapter 5.1 pp. 92-94

dehydration (condensation) reaction : a chemical reaction in which two biological molecules combine to form one single molecule, together with the loss of a water molecule.

hydrolysis: a chemcal reaction in which a polymer is broken into smaller molecules by adding the elements of a water molecule (2 hydrogen atoms and an oxygen atom).

hydrophilic: a physical property of a molecule that allow hydrogen bonding with water molecules. Hydrophilic molecules are generally soluble in water and other polar solvents.

monomer: a small molecule that may become chemically bonded to other monomers to form a polymer.

organic molecule: any member of a large class of chemical compounds whose molecules contain carbon. Exceptions to this rule include most carbon oxides, most cyanides (compounds with the -CN ion), thiocyanates (compounds with the -SCN ion), and elemental carbon.

polymer: a molecule composed of repeating structural units, (monomers), connected by covalent chemical bonds.

Carbohydrates, lipids, proteins: Chapter 5.2-5.3 pp. 95-102

amino acid: a molecule that contains both amine (NH4) and carboxyl (COOH) functional groups. Amino acids are the monomers of proteins.

carbohydrate: a simple organic molecule consisting of carbon, hydrogen, and oxygen, usually in a 1:2:1 ratio. Carbohydrates are found in all living things and serve many important functions for the cell.

denaturation (n), denature (v): alteration of a protein shape through some form of external stress such a way that it will no longer be able to carry out its cellular function. Denaturation may be reversible or irreversible.

fatty acid: a biological compound consisting of a carboxyl group (O==C--O--H) and a nonpolar chain of carbons and hydrogens. Fatty acids are monomers of triglyserides, a type of lipid.

hydrogen bond: a relatively weak chemical interaction (as compared to ionic bonds or covalent bonds) where an atom of oxygen, nitrogen, or flourine from one molecule is attracted to a hydrogen atom that is covalently bonded to another atom of oxygen, nitrogen, or flourine from another molecule. This phenomenon is generally associated with interactions between water molecules and most biological molecules (e.g. proteins, carbohydrates, nucleic acid).

---C--O---H < hydrogen bond> O===C----

hydrophobic: refers to the physical property of a molecule that is repelled from a mass of water. Hydrophobic molecules tend to be non-polar and thus are soluble in (or tend to dissolve) other neutral molecules and nonpolar solvents.

lipid: a biological molecule consisting mostly of carbon and hydrogen with smaller amounts of oxygen and phosphorus. As a general rule, lipids are nonpolar (therefore do not dissolve in water). They

function as energy storage molecules, heat storage molecules, and as a major structural component of membranes.

monosaccharide: a carbohydrate monomer.

polysaccharide: a carbohydrate polymer.

protein: Large organic compounds made of amino acids which are essential parts of all living organisms and participate in every process within cells.

Honors only:

Online resources: Chapter 5.4 “Closer Look”

primary structure: representation of a protein's structure as defined by its amino acid sequence.

quaternary structure: representation of a complex protein's structure as defined by the different polypeptide chains that comprise the entire protein. For example, the quaternary structure of hemoglobin is created by combining two alpha globulin chains and two beta globulin chains with a heme group.

secondary structure: representation of a protein's three dimensional structure such that the sequence of amino acids is influenced by hydrogen bonding. Examples of secondary structures of proteins include the alpha helix (as seen in collagen) and the beta pleated sheet (as seen in silk).

tertiary structure: representation of a protein's precise three dimensional structure such that the primary and secondary structures are further influenced by hydrophobic interactions of the amino acids' "R" groups and by disulfide linkages between cysteine groups. The tertiary structure of a protein is the major factor in determining the shape of a protein's active site.


Activity 4, Investigating Photosynthesis and Respiration, Pre-lab Activity.(Standards 2.1.2, 2.3.1, 6.2.1GLEs 10.6.l, 10.6.t)

GOALS: In this lab activity, students will

Analyze the chemical equations for photosynthesis and respiration and identify the reactants and products of the reactions.

Explain the complementary nature of the processes of photosynthesis and respiration.

ACTIVITY OVERVIEW: A synopsis of this lesson follows: Students use pictures and molecular models to determine how matter and energy is cycled in photosynthesis and respiration.

CONTEXT: The concepts that we have been developing and how this activity serves as the ‘next step’ can be explained as follows:

In previous activities, students learned that plants use the sun directly to obtain energy and that ultimately, animals, including decomposers, eat other organisms to obtain energy which their body needs to survive. There is interdependence within any given ecosystem for a supply of energy. This energy moves up the food chain. It starts with the sun and is stored by plants, then herbivores, then primary, secondary, tertiary, and top carnivores. . At each increasing level of the food chain there is less available energy. This activity shows how the law of conservation of energy applies to ecosystems in that energy is not lost, but rather it changes form as is passes through a food chain/food web. Organisms at higher trophic levels pass on much less energy (in the form of body mass) than they receive.

Activity 6: McMush (Standards 2.1.2, 2.4.6GLEs 10.6.m, 10.6.r) GOALS: In this lab activity, students will

Identify the reagents used to test for the presence of certain organic and inorganic compounds and observe positive test results.

Identify the organic and inorganic compounds found in a fast food meal

Determine the nutritional value of a fast food meal based on lab results.

ACTIVITY OVERVIEW: A synopsis of this lesson is as follows: In this activity, students will use qualitative data to identify organic and inorganic compounds present in a fast food meal, including carbohydrates, protein, fat, vitamins and salt. Initially, students will test known substances for the presence of these compounds, then perform the same tests on the components of a McDonald’s Hamburger Happy Meal. The results from that procedure will allow students to hypothesize about how much nutrition a Happy Meal really provides based on organic and inorganic compound composition.

CONTEXT: The concepts that we have been developing and how this activity serves as the ‘next step’ can be explained as follows Everything you eat is composed of three macromolecules: carbohydrates, proteins, and fats. The cells in all living things contain these organic compounds as well as nucleic acids (another macromolecule) and inorganic compounds such as vitamins and minerals. This activity will lead well into the Energy in Foods activity, in which the potential energy in food can be measured. In addition, the McMush experience will flow into the Observing Mechanical and Chemical Digestion activity, in which the breakdown of the organic compounds found in food is explored, and the assimilation of those smaller molecules within the body is explored as well. At the end of this investigation, students should be able to use chemical tests to analyze food for organic and inorganic components, and determine whether a typical fast food lunch contains these organic and inorganic molecules.

SEARCH AND DESTROY

1. Distinguish between nonspecific and specific responses to microbial infections. Give one example of each.

2. What are the roles of antigens and antibodies in interacting with foreign substances?

3. Describe two ways the antibody/antigen association prevent a foreign substance or organism from causing illness in the host?

RUBRIC—SEARCH AND DESTROY ASSESSMENT

1. Distinguish between nonspecific and specific responses to microbial infections. Give one example of each.

Nonspecific responses are responses that the organism exhibits to any invader. These responses do not recognize the invader. They may include physical barriers (skin, mucus) or internal responses (inflammation, killing by white blood cells). Specific responses are unique to the infecting organism and feature a memory response. Examples include antibody responses.

Scoring:

2: Complete response—answer includes distinguishing characteristics of nonspecific responses and specific responses and one example of each.

1: Partial response—answer describes either response correctly with an appropriate example or describes both responses correctly but gives inadequate or no examples.

0: Incorrect response—answer does not describe either response correctly or description fails to distinguish the two responses or answer lists examples (adequate or inadequate) without giving distinguishing characteristics.

2. What are the roles of antigens and antibodies in interacting with foreign substances?

Antigens are molecules (or parts of molecules) found on the foreign substance. Antibodies are molecules produced by the host which bind specifically to antigens.

Scoring:

2: Complete response: answer meets criteria listed.

1: Partial response: answer describes the role of antibodies or antigens correctly but not both.

0: Incorrect response: answer does not describe either role correctly or the roles are reversed.

3. Describe two ways the antibody/antigen association prevent a foreign substance or organism from causing illness in the host?

Possible answers:

a. For a toxin, the association can change the chemical makeup of the toxin, rendering it harmless.b. For an invading organism or virus, the antibody can act as a marker to attract white blood cells to

attack and digest the invader.

Scoring:

2: Complete response: response clearly shows why an antibody/antigen binding can remove or reduce the danger of the invader to the host. Two different examples are given.

1: Partial response: only one example is given that meets criteria described above.

0: Incorrect response: answers do not explain why this type of binding removes or reduces danger to the host (i.e. the answer just assumes that antigen/antibody binding automatically removes the danger inherently).

McMUSH

You have been asked to write a letter to the CEO of McDonald’s regarding your findings in this lab. Write a letter that includes the following:

The purpose of the lab. How to test for each compound present in food, including positive results. What compounds are present in a McDonald’s Happy Meal. Whether a McDonald’s Happy Meal can be considered nutritionally balanced,

with data to support your decision. Recommendations for changes in the menu based on your findings.

Rubric For McMush Letter:

Characteristics of a level 3:

The respondent states a clear position about the nutritional value of a McDonald’s Happy Meal and recommendations for changes early in the letter. The respondent describes the experimental design in detail and presents results clearly and objectively. Sufficient rationales that support the position are scientifically accurate, are relevant to the position, and are persuasive. The respondent also suggests alternate Happy Meal options, describing how these alternatives are nutritionally favorable but still appealing to children. Transitions are smooth and logical. A strong concluding paragraph ties together all points made in the letter and suggests a possible course of action for the CEO of McDonalds.


The respondent states a clear position about the nutritional value of a McDonald’s Happy Meal and recommendations for changes early in the letter. The respondent describes the experimental design in detail and presents results clearly and objectively. Sufficient rationales that support the position are scientifically accurate, are relevant to the position, and are persuasive. Transitions are smooth and logical. The concluding paragraph ties together all points made in the letter. The letter contains few, if any, errors in standard written English, and these do not interfere with understanding.


The respondent states a position about the nutritional value of a McDonald’s Happy Meal and recommendations for changes. The respondent describes the experimental design and presents results appropriately (i.e. in graphical or tabular form), but it is difficult to follow the procedure or the results are described using subjective language (e.g. “there is too much fat” rather than “the meal is positive for fat”). There is a concluding paragraph, but it may not tie together all points made in the letter. The letter may contain some errors in standard written English that rarely interfere with understanding.

Characteristics of a level 0

The respondent fails to state a position about the nutritional value of a McDonalds Happy Meal or about recommendations for changes. The respondent gives a vague description of the experimental design (or no description) and results are not displayed in graphical or tabular form. Results may be described subjectively. Conclusions about the data may be illogical or irrelevant. There is a general lack of unity, and no concluding paragraph exists. The response lacks any discernable purpose. The word choice is often general, repetitive, and/or confusing. Frequent and severe errors in standard written English interfere with understanding. The tone of the letter may be inappropriately emotional.

JANUARY

Topic 9: Energy in Living Systems

Standards:

2.4.4: Energy is transformed in chemical reactions. Energy diagrams can illustrate this transformation. Exothermic reactions release energy. Endothermic reactions absorb energy.

3.1.6: Chemical energy is derived from the making and breaking of chemical bonds.

6.2.2: Plant cells contain chloroplasts, which convert light energy into chemical energy through the process of photosynthesis. This chemical energy is used by the plants to convert carbon dioxide and water into glucose molecules, that may be used for energy or to form plant structures. Photosynthesis adds oxygen to the atmosphere and removes carbon dioxide.

6.2.3: All organisms, including plants, use the process of cellular respiration to transform stored energy in food molecules into usable energy. The energy produced is stored in the form of ATP and is used by organisms to conduct their life processes. Cellular respiration may require oxygen and adds carbon dioxide to the atmosphere.

6.2.4. Photosynthesis and cellular respiration are complementary processes resulting in the flow of energy and the cycling of matter in ecosystems.

GLEs:

10.6.q: Explain the processes used by autotrophs to transform light energy into chemical energy in the form of simple sugars. Give examples of how these compounds are used by living things as sources of matter and energy.

10.6.s: Describe photosynthesis as an energy storing process and explain how environmental factors such as temperature, light intensity, and the amount of water available can affect photosynthesis.

10.6.t: Identify the reactants and the products in equations that represent photosynthesis and cellular respiration. Explain how the equations demonstrate the Law of Conservation of Matter and Energy in terms of balanced equations.

10.6.u: Investigate and describe the complementary relationship (cycling of matter and the flow of energy) between photosynthesis and cellular respiration.

10.6.v: Recognize that during photosynthesis, plants use energy from the sun and elements from the atmosphere and the soil to make specific compounds. Recognize that these compounds are used by living things as sources of matter and energy.

10.6.w: Compare the amount of chemical potential energy stored in chemical bonds of a variety of foods (calorimetry). Recognize that equal amounts of different types of food contain different amounts of energy.

10.6.x: Recognize that during cellular respiration, chemical bonds between food molecules are broken (hydrolysis), and energy is transferred to ADP to create ATP (the energy storage molecule that fuels cellular processes). Acknowledge that all organisms must break the high energy chemical bonds in food molecules during cellular respiration to obtain the energy needed for life processes.

Assessments:

9. Photosynthesis and Respiration, questions 1a, 1b, 2, and 3.


Energy in Living Systems:

Chapter 7.1-7.3 pp. 136-144

ADP: Adenosine diphosphate, abbreviated ADP, is a nucleotide consisting of the nucleoside adenosine and two covalently bonded phosphate groups. ADP is cycled with ATP in energy transfer processes within the cell.

ATP: Adenosine triphosphate, abbreviated ATP, is a nucleotide consisting of the nucleoside adenosine and three covalently bonded phosphate groups. ADP is cycled with ATP in energy transfer processes within the cell. In the following hydrolysis reaction

ATP H2O <-----> ADP H3PO4

chemical energy is released in a form that is useful for cellular processes.

autotroph: an organism that produces its own organic compounds from carbon dioxide and an external energy source (either light or geochemical energy). Autotrophs are the producers in ecosystems.

calorie: a unit of energy defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius. One calorie is equivalent to 4.18 Joules (1 Joule = 1 kg-m2/sec2).

combustion: an energy releasing (exothermic) chemical reaction in which an organic compound combines with oxygen to produce carbon dioxide and water.

consumer: see "heterotroph"

heat: a form of energy transfer associated with motions of individual atoms, molecules, and ions.

heterotroph: an organism that obtains carbon and energy from organic molecules in the environment. Heterotrophs are the consumers and decomposers in ecosystems.

kilocalorie: one thousand calories. The kilocalorie (sometimes written as Calorie) is the unit of heat energy widely used in biochemical energy calculations.

kinetic energy: the energy possessed by an object due to its motion or the motion of its component particles.

photosynthesis: an energy requiring (endothermic) chemical reaction occurring in certain cells where carbon dioxide and water are consumed to produce biological molecules and oxygen. This reaction is energized by electromagnetic radiation (light).

potential energy: in the case of chemical energy, the energy released in exothermic chemical reactions.

producer: see "autotroph"

respiration: a combustion reaction occurring in living cells in which organic compounds are oxidized to carbon dioxide, and some of the energy released by this reaction is used to produce ATP from ADP and inorganic phosphate residues.

thermal energy: the total kinetic energy of the atoms of a substance.

work: the amount of mechanical energy transferred to an object by an external force.

Photosynthesis and the Carbon Cycle:

Chapter 8.4 pp. 172-173

carbon cycle: a series of global biochemical reactions in which carbon cycles between carbon dioxide and organic carbon through the processes of photosynthesis and respiration.

greenhouse effect : the phenomenon caused by absorption of infrared radiation by certain atmospheric gases. This absorption results in a gradual increase in surface temperature of the Earth (or other planet where the phenomenon occurs).

(Honors only) Details about photosynthesis and respiration

Chapter 7.4-7.6 pp. 145-155

aerobic: requiring oxygen or occurring in the presence of oxygen.

anaerobic: not requiring oxygen, harmed by oxygen, or occurring in the absence of oxygen.

electron transfer: in cells, a process where molecules move electrons from one electron carrier to another. This usually occurs with membrane bound electron carriers. The energy associated with electron transfer is used to create ATP for cellular work.

fermentation: oxidation of organic molecules in cells where the final electron acceptor is an organic molecule. Fermentation is an anaerobic process and produces small amounts of ATP relative to respiration.

glycolysis: The first stage of respiration in many cells. During glycolysis, a six carbon carbohydrate (usually glucose) is converted to two three-carbon molecules with a release of reduced NADH and ATP.

Krebs Cycle: the second stage of aerobic respiration. In the Krebs cycle, the carbons from the starting carbohydrate are oxidized to carbon dioxide. The Krebs cycle produces some ATP and reduced electron carriers (NADH and FADH2) which are oxidized in the electron transport system to produce large amounts of ATP.

lactic acid: the end product of fermentation of glucose in muscle cells. When the muscle cells are exposed to oxygen, the lactic acid is oxidize.

NAD/NADH: nicotinamide adenine dinucleotide--an elecron carrier in respiration that transfers electrons from organic molecules during glycolysis and the Krebs Cycle to other membrane bound electron carriers, allowing the production of ATP for the cell.

(Honors only) Chapter 8.1-8.3

Calvin Cycle: a series of biochemical reactions occurring in the light independent reactions of photosynthesis in which carbon dioxide is incorporated ("fixed") into organic compounds.

chlorophyll: a green photosynthetic pigment which donates a pair of electrons to electron carriers when energized by a photon of light.

electromagnetic spectrum: a range of wavelengths of energies traveling at 3 X 10^8 m/sec. Electromagnetic waves range from wavelengths of one picometer (gamma rays, high energy) to thousands of kilometers (radio waves, low energy). Visible light is in this spectrum with wavelengths from 400 nanometers (violet light) to 700 nanometers (red light).

electron acceptor: in an electron transfer system, a molecule or atom that receives electrons from another molecule or atom (called an electron donor).

electron carrier: in an electron transfer system, a molecule that accepts electrons from one molecule and donates electrons to another molecule.

excited state: a state of an atom where electrons have been energized to higher energy levels. This is an unstable state, and the electrons quickly return to the lower energy levels.

ground state: the stable state of an atom where no electrons are in higher energy levels.

light reaction: the chemical reactions in photosynthesis that require electromagnetic radiation (light) to occur. The light reaction causes an electron transport chain to create ATP.

NADP/NADPH: nicotinamide adenine dinucleotide phosphate--the final electron carrier in the light reaction of photosynthesis. The reduced form of this molecule (NADPH) carries electrons to molecules involved with carbon dioxide fixation in the Calvin Cycle.

photosystem: a cluster of membrane bound electron carriers involved with the light reaction of photosynthesis, including a photosensitive pigment such as chlorophyll.

pigment: a colored molecule of biological origin which undergoes a chemical change when exposed to light energy.


Activity 7: Energy in Foods GOALS: In this lab activity, students will

Use a computer/probe interface to measure temperature changes.

Monitor the energy given off by food as it burns.

Determine the energy content of several foods (Kcal).

Explain how the law of conservation of energy and matter are upheld.

Design and conduct an experiment to investigate the energy content of foods.

Note whether the foods high in lipid, carbohydrates, or proteins have the highest energy.

Relate the energy and matter in food to photosynthesis and respiration.

ACTIVITY OVERVIEW: A synopsis of this lesson is as follows In Part A of this activity, students will determine the energy content of food by burning a peanut and capturing the heat gained by a known amount of water. The law of conservation of energy states that the energy lost by the food should equal the energy gained by the water and the environment. Because only the heat gained by the water will be measured and not the environment, the energy values calculated will be lower than the actual values for the food tested. In Part B of this investigation teams will design an experiment to look for patterns in the amount of energy released during burning of different foods.

CONTEXT: The concepts that we have been developing and how this activity serves as the ‘next step’ can be explained as follows… Students have learned in previous activities that organisms must obtain food, either through photosynthesis or through food consumption, in order to obtain the energy necessary to sustain life processes. That energy is released by the oxidation of food (glucose) during cellular respiration. Many organisms consume carbohydrates, lipids and fats as part of their diet. The primary fuels for energy conversion are carbohydrates. Proteins and lipids may also be converted to energy, but only after the carbohydrate reserve is used up. Not all types of food molecules possess equal energy conversion values.

Activity 4: Investigating Photosynthesis and Respiration Lab:


Use data from investigations of photosynthesis and cellular respiration to explain how autotrophs capture light energy and produce molecules such as simple sugars and starch and how organisms break down the high-energy compounds in foods to obtain energy for conducting life processes.

Measure the rates of photosynthesis and cellular respiration and recognize whether each of these reactions is endothermic or exothermic.

Design investigations to develop reasonable explanations concerning the complementary relationship between photosynthesis and respiration.

ACTIVITY OVERVIEW: A synopsis of this lesson is as follows: Students measure the change in CO2 content in a closed container with various organisms to indirectly determine the rate of photosynthesis. Then, students design and carry out their own investigations in order to test the effects of different variables on photosynthesis and/or respiration in plants and/or animals.

CONTEXT: The concepts that we have been developing and how this activity serves as the ‘next step’ can be explained as follows In previous activities, students learned that plants use the sun directly to obtain energy and that ultimately, animals, including decomposers, eat other organisms to obtain energy which their body needs to survive. There is interdependence within any given ecosystem for a supply of energy. This energy moves up the food chain. In this activity, students will recognize that the energy for most living things is collected from the sun by green plants during the process of photosynthesis and this energy is released and made available to do cell work by the process of cellular respiration.

Topic 10: Enzymes

Standards:

1.1.3. Understand that: Theories in science are well-established explanations of natural phenomena that are supported by many confirmed observations and verified hypotheses. The application of theories allows people to make reasonable predictions. Theories may be amended to become more complete with the introduction of new evidence.

1.1.4 Understand that: Investigating most real-world problems requires building upon previous scientific findings and cooperation among individuals with knowledge and expertise from a variety of scientific fields. The results of scientific studies are considered valid when subjected to critical review where contradictions are resolved and the explanation is confirmed.

1.1.6 Understand that: Knowledge and skill from sources other than science are essential to scientific inquiry. These include mathematics, reading, writing, and technology.

2.4.3 The rate of a chemical reaction depends on the properties and concentration of the reactants, temperature, and the presence or absence of a catalyst.

2.4.5 A catalyst lowers the activation energy of a chemical reaction. The catalyst remains unchanged and is not consumed in the overall reaction. Enzymes are protein molecules that catalyze chemical reactions in living systems.

6.1.1 In order to establish and maintain their complex organization and structure, organisms must obtain, transform, and transport matter and energy, eliminate waste products, and coordinate their internal activities.

6.2.1 Cells carry out a variety of chemical transformations (i.e., cellular respiration, photosynthesis, and digestion) which allow conversion of energy from one form to another, the breakdown of molecules into smaller units, and the building of larger molecules from smaller ones. Most of these transformations are made possible by protein catalysts called enzymes.

6.4.2 The scientific investigation of cellular chemistry enables the biotechnology industry to produce medicines, foods, and other products for the benefit of society.

GLEs:

10.1.c Collect accurate and precise data through the selection and use of tools and technologies appropriate to the investigations. Display and organize data through the use of tables, diagrams, graphs, and other organizers that allow analysis and comparison with known information and allow for replication of results.

10.1.d Construct logical scientific explanations and present arguments which defend proposed explanations through the use of closely examined evidence.

10.6.m Observe formulas and diagrams of compounds found in food (fats, proteins, carbohydrates). Identify elements that comprise these compounds.

10.6.n Explain that physically breaking down food into smaller pieces by mechanical digestion helps facilitate breakdown (by increasing surface area) into chemical components and that digestive enzymes are necessary for the breakdown of food into those chemical components (e.g., starch to glucose, lipids and glycerol to fatty acids, proteins to amino acids).

10.6.o Observe and recognize that unicellular organisms take in food from their environment and chemically digest it (if needed) within their cell body.

10.6.p Recognize that both mechanical and chemical processes are necessary in digestion for multi-cellular organisms to get molecules that come from food to enter the cells. Trace the process

whereby nutrients are transported to cells where they serve as building blocks for the synthesis of body structures and as reactants for cellular respiration.

10.6.y Investigate the role of enzymes (e.g., protease, amylase and lipase) in the rate of chemical breakdown of a variety of foods.

10.6.z Explain how enzymes permit low temperature chemical reactions to occur in cells.

10.6.aa Investigate how various factors (temperature, pH, enzyme/substrate concentration) affect the rate of enzyme activity.

Assessment:

Lab Report: Enzymes (teacher’s choice)


Enzymes

Chapter 5.5 pp. 103-105

activation energy: in any chemical reaction, the energy necessary to break bonds in the reactants.

catalyst: any agent (usually chemical) that facilitates or speeds up a chemical reaction by lowering activation energy. A catalyst is not consumed by the reaction because it is not a reactant.

enzyme: a protein catalyst produced in cells.

substrate: the reactant or reactants involved in a chemical reaction that is catalyzed by an enzyme.


Activity 8: Observing Mechanical and Chemical Digestion (Standards: 6.1.1, 6.2.1GLEs: 10.6.m, 10.6.n, 10.6.o, 10.6.p)


Look at the roles that mechanical and chemical digestion play in the breakdown of food into small molecules.

Analyze the presence of enzymes involved in decomposition reactions.

Interpret how the molecules in food are eventually used by the body for growth and repair.

ACTIVITY OVERVIEW: A synopsis of this lesson is as follows: In this activity, students will experiment with several digestive enzymes found in the human body (pancreatin, amylase, bile salts) and observe how they affect the process of chemical digestion. In

addition, students will examine how mechanical digestion differs from chemical digestion. Students will be able to explain that physically breaking down food into smaller pieces by mechanical digestion helps facilitate digestion into chemical components and that digestive enzymes are necessary for the breakdown of food into those chemical components.

CONTEXT: The concepts that we have been developing and how this activity serves as the ‘next step’ can be explained as follows: Students have learned in previous activities that organisms must obtain food, either through photosynthesis or through actual food consumption, in order to obtain the energy necessary to sustain life processes. That energy is released during cellular respiration, some of which is used to add a phosphate to ADP to create ATP. This energy is subsequently stored in the bonds of ATP. This activity allows the student to observe how digestion enables the body to break down food into small enough molecules that they can be taken up by cells and used for energy, growth and repair. Humans as well as many other heterotrophs use enzymes to break down complex carbohydrates, lipids and proteins as they pass from the mouth to the stomach and on to the small intestines of their digestive systems. Digestion of food results in molecules small enough to be absorbed by individual cells in the body. There are two types of digestion: mechanical and chemical. Mechanical involves the physical ripping apart of food whereas chemical involves chemical digestion of food into smaller molecules. Chemical digestion is facilitated by enzymes. Students will learn about enzymes in-depth during the enzyme labs following this activity.

Activity 10: Investigating Enzyme Action with Beano (Standards: 1.1.3, 1.1.4, 2.4.3, 2.4.5, 6.2.1, 6.4.2GLEs 10.1.c, 10.1.d, 10.6.n, 10.6.y, 10.6.z, 10.6.aa)


Determine how digestive enzymes work.

Determine what factors might affect an enzyme-catalyzed reaction.

Determine whether an enzyme dietary supplement like Beano is effective in aiding the human digestion of carbohydrates.

ACTIVITY OVERVIEW: A synopsis of this lesson is as follows:

This activity is designed to allow the student to observe how digestive enzymes act on macromolecules, specifically complex carbohydrates. While there are other digestive enzymes in the body like pancreatin, amylase and pepsin, this activity focuses on commercially produced carbohydrate decomposing enzymes, specifically an enzyme created by the researchers at Lactaid, Inc. called Beano (TM). The breakdown of certain complex sugars by bacteria in the large intestine naturally results in the creation of gas as a byproduct. There are some foods that result in more gas production than others, and this activity explores exactly how Beano (TM) works to eliminate, or at least dramatically reduce, the amount of gas normally produced. Students will be able to observe the breakdown of complex carbohydrates into simple carbohydrates by measuring the amount of glucose present in a bean solution at timed intervals.


In the activity “Observing Mechanical and Chemical Digestion”, students learned that humans and

many other heterotrophs utilize chemical digestion by way of enzymes to break down complex carbohydrates, lipids and proteins as they pass from the mouth to the stomach and on to the small intestines of their digestive systems. If it were not for the presence of these specific enzymes, the food we eat would never be reduced into small enough molecules to be utilized by our bodies at the cellular level for life processes like growth and repair. During chemical digestion, however, some intestinal gas is created. This typically happens in the large intestine as the result of breaking down complex carbohydrates. This activity is the final activity in the Digestion and Assimilation subunit of the Chemical Biology unit, and ties together chemical digestion, enzymes and substrates, and the roles of biomolecules in body function.

(Honors only--may be done in addition to or in place of Activity 10) Activity 9: Investigating Enzyme Action--catalase(Standards: 1.1.3, 1.1.4, 1.1.6, 2.4.3, 2.4.5, 6.2.1, 6.4.2GLEs: 10.1.c, 10.1.d, 10.6.n, 10.6.y, 10.6.z, 10.6.aa)


Observe the enzyme catalase at work in organisms from different kingdoms.

Learn about the specificity of enzyme catalyzed reactions.

Understand the importance of the practical applications of enzyme catalyzed reactions.

Determine what factors might affect an enzyme-catalyzed reaction.

Understand what happens to enzymes after they catalyze a reaction.


Instruction is organized around a model based on the constructivist philosophy of learning in which learners build new ideas on top of their old ideas. The constructivist model used in “Enzyme Action” is the five “E” model: Engage, Explore, Explain, Elaborate, and Evaluate. This model allows students to experience common activities, to use and build on prior knowledge and experience, to construct meaning, and continually assess their understanding.

Engage: This short engagement activity is designed to stimulate student interest in the catalase/H2O2 reaction by having students observe the oxygen gas bubbles that are produced during the catalytic process. By testing the reaction in yeast, potato, and beef liver, students learn that the enzyme reaction is common to organisms representing the fungi, plant and animal kingdoms.

Explore: In this exploration activity students read about enzymes while working in teams. Since each of the four sets of readings contains information about different aspects of enzyme action, students must share their information with the whole class in order to learn all the key concepts about enzymes.

Explain: In this lab activity students use a computer, a gas pressure sensor, and Logger Pro software to measure the rate of the catalase reaction in a yeast suspension. It is during this activity that students acquire skills in using the lab equipment that are necessary for conducting the inquiry activity in the “Student Designed Experiment” activity which follows.

Elaborate: Students design and carry out their own experiments investigating some aspect of enzyme activity.

Evaluate: Students answer summary questions.


In the activity “Observing Mechanical and Chemical Digestion”, students learned that humans and many other heterotrophs utilize chemical digestion by way of enzymes to break down complex carbohydrates, lipids and proteins as they pass from the mouth to the stomach and on to the small intestines of their digestive systems. If it were not for the presence of these specific enzymes, the food we eat would never be reduced into small enough molecules, and would therefore never be able to be utilized by our bodies at the cellular level for growth and repair. However, enzymes catalyze more than just digestion reactions. They catalyze many of the chemical reactions which occur in living things. Students learn about enzyme action and factors which affect their efficiency throughout these sets of activities. This activity is the final activity in the Digestion and Assimilation subunit of the Chemical Biology unit, and ties together chemical digestion, enzymes and substrates, and the roles of biomolecules in body function.

Photosynthesis and Cellular Respiration AssessmentIntroduction

In a science class, students were conducting an experiment. They placed a plant in a sealed container with a tool that can measure the amount of carbon dioxide and oxygen present inside the container. The container was placed in sunlight for eight hours of the day. The rest of the day, it was placed in the dark. Data collected during the time that the container was exposed to light are shown in the graph below:

1. a. Describe what happens to the concentrations of carbon dioxide and oxygen inside the container while exposed to light.

1. b. Explain why these changes occurred.

Con

cent

ratio

n of

gas

(p

pm)

O2

CO2

Time (hours)

1. c. How do these changes relate to the process of photosynthesis, which is shown in the equation 6CO2 + 6H2O light C6H12O6 + 6O2?

Data collected during the time that the container was placed in the dark are shown in the graph below:

2. a. Describe what happens to the concentrations of carbon dioxide and oxygen inside the container while placed in the dark.

Con

cent

ratio

n of

gas

(p

pm)

CO2

O2

Time (hours)


3. The next day, the students in the science class repeated the same experiment, but now introduced an insect into the container with the plant. The container was placed in sunlight and data collected over eight hours is shown in the graph below:

Compare the results of this experiment to the results of the first experiment. Explain why these data are different.

Con

cent

ratio

n of

gas

(p

pm) CO2

O2

Time (hours)

4. a. Of the three choices below, select the graph which best represents what the graph would look like if the container with the insect and the plant was placed in the dark for the rest of the day.

A.

B.

C.

Con

cent

ratio

n of

gas

(p

pm) CO2

O2

Con

cent

ratio

n of

gas

(p

pm)

CO2

O2

Con

cent

ratio

n of

gas

(p

pm)

CO2

Time (hours)

Time (hours)

Explain why this graph best represents your prediction.

5. Recently, while shopping for gifts at the mall, Catherine and Brian found a unique tem. They found a sealed glass globe that contains water, an aquatic plant, a small fish and bacteria. In other words, it’s an ecosystem that is completely closed off from the outside world! Catherine and Brian took the globe home and placed it under a grow light which stayed lit for seven hours each day.

O2

Time (hours)

a. Describe how each organism in the globe allows the other two organisms to survive in this closed environment.

5. b. Choose two of the following compounds and explain how the living things in

this ecosystem transform these compounds through chemical reactions.

H2O CO2 O2 carbohydrates

Rubric--Photosynthesis and Cellular Respiration Assessment

1. a. Describe what happens to the concentrations of carbon dioxide and oxygen inside the container while exposed to light.


Student states that the level of CO2 decreases and the level of O2 increases at the same rate.


Student states that either CO2 level decreases or that the level of O2 increases.


Student states that either CO2 level increases or that O2 level decreases or that the gas level changes (without an indication of the direction of change).



Student states that in this situation photosynthesis is occurring. In the light, the level of CO2 consumption exceeds the level of CO2 production. Likewise, the level of O2 production exceeds the level of O2 consumption. (NOTE: student does not need to mention that respiration is also occurring to qualify for a complete response).


Student states that in this situation photosynthesis is occurring but respiration is not or that photosynthesis consumes CO2 but doesn’t mention the effect on O2 or that photosynthesis produces O2 but doesn’t mention the effect on CO2.


Student response does not explain how levels of CO2 or O2 relate to photosynthesis or to respiration.

2. a. Describe what happens to the concentrations of carbon dioxide and oxygen inside the container while placed in the dark.


Student states that the level of CO2 increases and the level of O2 decreases at the same rate.


Student states that either CO2 level increases or that the level of O2 decreases.


Student states that either CO2 level decreases or that O2 level increases or that the gas level changes (without an indication of the direction of change).



Student states that in this situation photosynthesis is no longer occurring. In the dark, respiration is occurring; as a result, CO2 is produced but not consumed. Likewise, O2 is consumed but not produced.


Student states that in this situation that respiration produces CO2 but doesn’t mention the effect on O2 or that respiration consumes O2 but doesn’t mention the effect on CO2.


Student response does not explain how levels of CO2 or O2 relate to photosynthesis or to respiration or response states that photosynthesis is occurring.

3. The next day, the students in the science class repeated the same experiment, but now introduced an insect into the container with the plant. The container was placed in sunlight and data collected over eight hours is shown in the graph below:

Compare the results of this experiment to the results of the first experiment. Explain why these data are different.


Student states that in this situation photosynthesis is balanced by respiration. The insect carries out respiration but not photosynthesis. The rate of CO2 production is the same as the rate of CO2

consumption. Likewise, the rate of O2 production is the same as the rate of O2 consumption or the rate of change for both gases is zero.


Student states that in this situation that photosynthesis and respiration are both occurring but doesn’t refer to rate of change in gas concentration or mentions that the rate of consumption of both gases equals the rate of production of both gases but doesn’t explain why.


Student states that level of CO2 equals the level of O2 or that the plant undergoes photosynthesis only and the insect undergoes respiration only or any other incorrect response.

4 a. Of the three choices below, select the graph which best represents what the graph would look like if the container with the insect and the plant was placed in the dark for the rest of the day.

4 b. Explain why this graph best represents your prediction.


The correct choice is C. Student states that when the system is placed in the dark, photosynthesis eventually stops. Respiration in both plant and insect continues. In respiration, CO2 levels increase and O2 levels decrease.


Student chooses C and explains that photosynthesis stops and respiration begins. Response shows that student believes that respiration had not been occurring while the plant was in the light.


Student does not choose C or student explanation does not address photosynthesis or respiration or any other incorrect response.

Recently, while shopping for gifts at the mall, Catherine and Brian found a unique tem. They found a sealed glass globe that contains water, an aquatic plant, a small fish and bacteria. In other words, it’s an ecosystem that is completely closed off from the outside world! Catherine and Brian took the globe home and placed it under a grow light which stayed lit for seven hours each day.

5. a. Describe how each organism in the globe allows the other two organisms to survive in this closed environment.


The plant provides food and oxygen (through photosynthesis) for the fish and for the bacteria.

The fish provides food (body waste) for the bacteria and CO2 (from respiration) and nutrients to the plant or the fish grazes off the plant to prevent it from overgrowing the globe.

The bacteria remove wastes for the benefit of the fish and the plant.


Meets two of the criteria listed above. Information about the third organism is either missing or incorrect.


Meets less than two of the criteria listed above. Information about two or more of the organisms is either missing or incorrect.

5 b. Choose two of the following compounds and explain how the living things in this ecosystem transform these compounds through chemical reactions.

H2O CO2 O2 carbohydrates


Response meets two of the following criteria.

H2O: plants use this molecule in photosynthesis and transform it to O2. insects and bacteria produce this molecule from O2 during respiration.

CO2: plants use this molecule in photosynthesis to build carbohydrates.insects and bacteria produce this molecule as a waste product of respiration from carbohydrates

O2: plants produce this molecule in photosynthesis as a waste product from H2O. insects and bacteria use this molecule in respiration and transform it to H2O

carbohydrate: plants produce this during photosynthesis from CO2

animals use this molecule for energy in respiration and transform it to CO2

Student may include the equations for photosynthesis and respiration, but this is not needed (nor is it sufficient) for a complete response


Response meets one of the following criteria.


Response does not match any of the criteria or student writes the chemical equation for either (or both of) photosynthesis or respiration with no explanation.

FEBRUARY

Topic 11: Cells and Cell Size

Standards:

1.1.4. Understand that: Investigating most real-world problems requires building upon previous scientific findings and cooperation among individuals with knowledge and expertise from a variety of scientific fields. The results of scientific studies are considered valid when subjected to critical review where contradictions are resolved and the explanation is confirmed.

6.1.1. In order to establish and maintain their complex organization and structure, organisms must obtain, transform, and transport matter and energy, eliminate waste products, and coordinate their internal activities.


6.1.3. Cells have distinct and separate structures (organelles), which perform and monitor processes essential for survival of the cell (e.g., energy use, waste disposal, synthesis of new molecules, and storage of genetic material). The highly specific function of each organelle is directly related to its structure.


GLEs:

10.1.d. Construct logical scientific explanations and present arguments which defend proposed explanations through the use of closely examined evidence.

10.6.a. Use microscopes to identify similarities and differences among a variety of cells (e.g., muscle, nerve, epithelial, blood, adipose), and explain how structural variations relate to the function that each of the cells performs.

10.6.b. Differentiate between prokaryotic cells and eukaryotic cells in terms of their general structures (cell membrane & genetic material) and degree of complexity. Give examples of prokaryotic organisms and organisms with eukaryotic cells.

10.6.c. Explain how organelles of single-celled organisms function as a system to perform the same basic life processes as are performed in multi-cellular organisms (e.g., acquisition of energy, elimination of waste, reproduction, gas exchange, growth, repair, and protein synthesis).

10.6.i. Construct cell models (e.g., phenolphthalein-agar cubes, potato-iodine cubes) to investigate the relationship among cell size, surface area to volume ratio and the rates of diffusion into and out of the cell. Explain why large organisms have developed from many cells rather than one large cell.

10.6.k. Explain how the cells of a multi-cellular organisms work together for the benefit of the colonial or singular organism.

Asessments:

10. Group assignment: Design a Cell11. Cells and Cell Size, questions 1 and 2


Cells and Cell Size

Chapter 6.1 pp.110-114

Chapter 6.4 (optional) pp. 124-127Chapter 6.5 pp. 128-129

cell theory: statement that all living things are made of cells, and that all cells come from pre-existing cells.

cell wall: a rigid structure surrounding plant cells, fungus cells, and most bacterial cells that protects the cell from bursting in dilute solutions.

chloroplast: organelle found in plant cells in which photosynthesis occurs.

cytoplasm: thick jellylike substance found in cells in which the chemical reactions of the cell take place.

eukaryote (n) -tic (adj): organism consisting of one or more cells in which DNA is contained in a membrane bound nucleus. Eukaryotes also possess many membrane bound organelles.

membrane: Lipid barrier surrounding a cell which controls traffic of dissolved substances in and out of the cell.

micrometer: 1/1000 of one millimeter.

mitochondrion (s) -ia (pl): organelle found in all eukaryotes in which aerobic respiration occurs and ATP is formed.

nucleus: membrane bound organelle in eukaryotic cells which contains the cellular DNA, arranged in chromosomes.

organelle: structure in a cell with a specific function.

prokaryote (n) -tic (adj): single cell organism in which the cellular DNA is not contained in a membrane bound nucleus. All prokaryotes are bacteria, and the only true organelles prokaryotes possess are ribosomes.

optional (from 6.4)

chromatin (see Cell Cycle and Cancer): combination of DNA and protein found in the nucleus of eukaryotes.

endoplasmic reticulum: a protein network found inside eukaryotic cells which transports proteins and other molecules within the cytoplasm.

Golgi apparatus: membrane bound structure which packages molecules for export out of the cell via exocytosis.

lysosome: vesicle found inside eukaryotic cells which contains digestive enzymes whose function is to digest worn out cell parts and to digest intracellular invaders (e.g. viruses).

nucleolus: structure found inside the nucleus of eukaryotic cells in which RNA synthesis (transcription) occurs.

ribosome (see DNA and the Genetic Code): organelle found in all cells in which protein synthesis occurs in conjunction with mRNA.

vacuole: membrane bound vesicle in eukaryotic cells used to store excess water and dissolved substances.

vesicle: membrane bound sac which functions in moving dissolved substances into and out of cells.


Activity 5: Cell Structure and Function (Standards: 1.1.4, 6.1.1, 6.1.2, 6.1.3, 6.1.8GLEs: 10.1.d, 10.6.a, 10.6.b, 10.6.c)


Observe the differences between prokaryotic and eukaryotic cells.

Observe that cells take highly varied forms in different plants, animals and microorganisms.

Observe and identify distinct organelles which perform processes necessary for survival.


This activity is designed to be an introductory lesson in cell structure and function. Students will observe six microscope slides to examine the differences between prokaryotic and eukaryotic cells, to examine the different types of structures found in cells, as well as propose explanations for the functions of these structures. Students will then observe an unknown cell specimen and classify it based on their observations made during the first part of the lab.


Students have learned how cells carry out a variety of chemical transformations such as cellular respiration, photosynthesis and digestion, which allow conversion of energy from one form to another, the breakdown of molecules into smaller units and the building of larger molecules from smaller ones. In this activity, students learn that it is at the cellular level that these reactions take place.

Activity 13: Investigating Cell Size: (Standards: 6.1.2, 6.1.8GLEs: 10.6.i, 10.6.k)


Observe different shapes of different sizes and calculate surface area to volume ratios.

Determine how the size of a cell affects its efficiency at obtaining nutrients.

Speculate on the limiting factors on cell size.

ACTIVITY OVERVIEW: A synopsis of this lesson is as follows: This activity is designed to allow the student to explore why cells are so small. Students will look at relationships between surface areas and volumes of simulated cells in order to make some generalizations about basic geometric principles as they relate to sizes and shapes of cells and/or organisms. In Part A of the activity, students will explore what happens to the surface areas, volumes, and the ratio of surface area to volume as the size of a cell increases. In Part B of the investigation, students will explore the effect that shape has in surface area to volume ratios. In Part C, students will explore the effects of flattening and/or elongating on the surface area to volume ratio. In Part D, students actually model the diffusion of materials into a “cell” using a agar cubes and phenolphthalein. At the end of this activity, students will be able to determine how the size of a cell affects its efficiency at obtaining nutrients and relate that to why cells are so small.


Students have learned that in order to survive, cells must constantly interact with their surrounding environment. Gases and food molecules dissolved in water must be absorbed and waste products must be eliminated. For most cells, this passage of all materials in and out of the cell must occur through the cell membrane. Each internal part of the cell has to be served by part of the cell surface. As a cell grows bigger, its internal volume enlarges and the cell membrane expands. Unfortunately, the volume increases more rapidly than does the surface area, and so the relative amount of surface area available to pass materials to a unit volume of the cell steadily decreases. The important point is that the surface area to the volume ratio gets smaller as the cell gets larger. If the cell grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular volume. When this happens, the cell must divide into smaller cells with more efficient surface area/volume ratios, or it will die.

Topic 12: Osmosis and Diffusion/Active Transport

Standards:

6.1.4. The cell membrane is dynamic and interacts with internal membranous structures as materials are transported into and out of the cell.

6.1.5. The transportation of materials across the membrane can be passive (does not require the expenditure of cellular energy), or active (requires the expenditure of cellular energy) depending upon membrane structure and concentration gradients.

GLEs:

10.6.d. Use fluid mosaic models of the plasma membrane to explain how its structure regulates the movement of materials across the membrane.

10.6.e. Show how water moves in and out of cells down a concentration gradient. Recognize that this process, known as osmosis, requires no input of energy.

10.6.f. Explain the role of cell membranes as highly selective barriers (e.g., diffusion, osmosis, active transport).

10.6.g. Distinguish between active and passive transport. Recognize that active transport requires energy input to move molecules from an area of low concentration to an area of high concentration (against the concentration gradient).

10.6.h. Design a controlled experiment to investigate the capacity of the cell membrane to regulate how materials enter and leave the cell.

Assessments:

12. Osmosis and Diffusion, questions 1 and 2.


Osmosis and Diffusion

Chapter 6.2 pp. 115-117

Chapter 6.3 pp. 118-122

active transport: the movement of substances out of or into cells against a concentration gradient which requires ATP use by the cell.

diffusion: movement of substances from high concentrations to low concentrations without the expenditure of energy.

equilibrium: a thermodynamic state in which movement of materials in one direction is balanced by movement of materials in the opposite direction.

facilitated diffusion: movement of large molecules across a membrane by transport proteins along a concentration gradient.

nonpolar molecule: a molecule in which electric charges are equal throughout. Nonpolar molecules do not generally dissolve in polar solvents like water.

osmosis: diffusion of water along a concentration gradient across a semi-permeable membrane.

passive transport: diffusion of molecules along a concentration gradient across a semi-permeable membrane with no expenditure of energy.

permeable: referring to a barrier, able to cross.

phospholipid: a type of triglyceride consisting of a phosphate group and two fatty acid residues covalently bonded to a glycerol molecule. Phospholipids make up the primary structure of membranes since they have hydrophilic qualities (the phosphate group) and hydrophobic qualities (the fatty acid residues).

polar molecule: a molecule in which electric charges are located on opposite ends (a positive end and a negative end). Polar molecules and ions tend to dissolve in polar solvents like water.

selectively permeable (semi-permeable): referring to a membrane, capable of allowing some dissolved substances to cross but not others.

Selected Activities:

Activity 11: Using Bubbles to Explore Cell Membranes: (Standards: 6.1.4

GLEs: 10.6.d)


Examine the structure of the cell membrane by creating a model.

Analyze the properties of the cell membrane.

Relate the structure of the cell membrane to its function.


In this activity, students explore the structure of the cell membrane. It is hard to visualize the fluid mosaic model, and this activity attempts to make the fluid characteristic of the cell membrane more tangible. The cell membrane is composed of a double layer of phospholipids, with the hydrophilic heads pointing toward the watery external and internal environments, and with the hydrophobic tails pointing inward away from the watery environments. Embedded within these phospholipids are proteins. Phospholipids and proteins are not rigidly fixed in place – they can move around within the confines of the cell membrane itself. This property has implications for what functions the cell membrane can perform.


Students have learned that cells are the smallest units that can carry out basic life processes. They have learned about organelles and their functions, what makes prokaryotic cells different from eukaryotic cells, and what makes plant cells different from animal cells. Students have also learned that absorbed food molecules are utilized by cells as a source of energy and as a source of molecules for growth and repair. It is through the cell membrane that the materials needed by cells must pass, as well as materials that cells must get rid of must pass in order to maintain a stable internal environment. The next section of the Chemical Biology unit focuses on just this: how cells exchange materials with the environment. This activity is the students’ introduction to the dynamic structure of the cell membrane. The activity that immediately follows this, “Diffusion through Membranes” (a Science Van Project lab), will allow students to explore how the structure of the cell membrane influences how molecules move across them. This will include both active and passive transport processes. In the last activity of the “Exchanging Materials with the Environment” topic, students will explore why cells are so small.

Activity 12: Diffusion through Cell Membranes--low tech version (Standards: 6.1.4, 6.1.5GLEs: 10.6.d, 10.6.e, 10.6.f, 10.6.g, 10.6.h)


Use an egg to explore what happens during osmosis, or the diffusion of water across a membrane.


This activity provides students with the opportunity to observe the diffusion of water across a cell membrane. The concept of osmosis is rather abstract and this activity allows for a visual understanding of hypertonic, hypotonic and isotonic solutions.


Students have learned that in order to survive, cells must constantly interact with their surrounding environment. Gases and food molecules dissolved in water must be absorbed and waste products must be eliminated. For most cells, this passage of all materials in and out of the cell must occur through the cell membrane. The cell membrane is selectively permeable and regulates what can enter and leave the cell. Due to the nature of the membrane itself as well as particle size, concentration, and other factors – not all materials can enter and/or leave the cell without the cell having to expend energy. This investigation focuses on the passive transport mechanism of diffusion of water (osmosis). Students will combine what they will learn in “Diffusion through Membranes” with what they learned in the activity, “Investigating Cell Size” to explain the importance of the cell membrane in maintenance of a stable internal environment.

(Honors only) Activity 12: Diffusion through Cell Membranes--high tech version (note: this is done in place of the low tech version, not in addition to it)


determine the rate of diffusion of salt across a membrane into water.

design and conduct experiments to answer questions about factors which affect the rate of diffusion across membranes.


This activity is designed to allow the student to investigate some factors which influence what materials can enter and leave the cell through the process of diffusion through the membrane. In the first part of the investigation, students investigate the effect of concentration on a salt solution passing through a model of a cell membrane (dialysis tubing). In Part B of the investigation, students design and conduct their own experiments where they investigate the effect of various factors on the diffusion of materials through the model membrane.


Students have learned that in order to survive, cells must constantly interact with their surrounding environment. Gases and food molecules dissolved in water must be absorbed and waste products must be eliminated. For most cells, this passage of all materials in and out of the cell must occur through the cell membrane. The cell membrane is selectively permeable and regulates what can enter and leave the cell. Due to the nature of the membrane itself as well as particle size, concentration, and other factors – not all materials can enter and/or leave the cell without the cell having to expend energy. This investigation focuses on the passive transport mechanism of diffusion of water (osmosis). Students will combine what they will learn in “Diffusion through Membranes” with what they learned in the activity, “Investigating Cell Size” to explain the importance of the cell membrane in maintenance of a stable internal environment.

GROUP ASSIGNMENT—THE CELL

In this assignment, you will be assigned to a group of four to design a cell according to how it fulfills the functions of life.

You will make a poster of your cell, and you will create a representation of organelles according to the function they perform.

Your poster must show how the cell performs the following:

1) Selective barrier which allows some substances to enter and leave but prevents other substances from entering and leaving.

2) Ability to transform energy into biologically useful forms.

3) Ability to repair damaged parts; that is, to break down old or damaged parts and make new cell parts out of materials in the cell.

4) Ability to store information.

The cell performs each of the four functions listed above using organelles, small structures within the cell. In your poster, you will draw a functional representation of the organelles which carry out each function listed above. A functional representation is a picture that shows what the structure does.

For example:

Cells must transform energy into biologically useful forms. In cells, the mitochondria produce energy for the cell.

If you look in the textbook, you’ll see something that looks like this:

Instead of this interesting shape, you’ll draw or create something that is associated with creating energy, like a battery, a campfire, or a lightning bolt. Use your imagination!

Your final project will consist of the following:

Your poster with functional representations of organelles. A written explanation of each organelles and how your functional representations match the true

function of each organelle.

RUBRIC: GROUP ASSIGNMENT—THE CELL

Selective barrier:

0 points: Poster does not identify cell membrane as the selective barrier or the function of the cell membrane is not correctly stated.

1 point: Poster identifies cell membrane as the selective barrier and the function of the cell membrane is correctly stated, but the representation on the poster is inconsistent with a selective barrier or a picture of a cell membrane is copied out of a biology textbook.

2 points: Poster identifies cell membrane as the selective barrier and the function of the cell membrane is correctly stated. The representation on the poster is consistent with a selective barrier (e.g. may be a gated fence, a toll booth, etc).

Ability to transform energy:

0 points: Poster does not identify mitochondria or chloroplasts as organelles that transform energy or functions of these are not correctly stated.

1 point: Poster identifies mitochondria or chloroplasts as organelles that transform energy, but the representation on the poster is inconsistent with these organelles or pictures of chloroplasts or mitochondria are copied out of a biology textbook.

2 points: Poster identifies mitochondria or chloroplasts as organelles that transform energy and the functions of these organelles are correctly stated. The representation on the poster is consistent with the organelle’s function (e.g. a mitochondrion may be represented as a battery or a lit match, a chloroplast may be represented as a mirror or a solar cell).

Repair damaged parts:

0 points: Poster does not identify ribosomes as a protein factory nor lysosomes as a means to digest worn out parts or functions of these are not correctly stated.

1 point: Poster identifies ribosomes as protein factories or lysosomes as organelles that digest worn out parts but the representation on the poster is inconsistent with these organelles or pictures of the organelles are copied out of a biology textbook.

2 points: Poster identifies ribosomes as protein factories or lysosomes as organelles that digest worn out parts. The representation on the poster is consistent with the organelle’s function (e.g. a ribosome may be represented as a factory or a bakery. A lysosome may be represented as a vacuum cleaner or a PacMan.)

Store information:

0 points: Poster does not identify the nucleus as the organelle that stores cellular information or the function of the nucleus is not correctly stated.

1 point: Poster identifies the nucleus as the organelle that stores cellular information but the representation on the poster is inconsistent with this function or a picture of a nucleus is copied out of a biology textbook.

2 points: Poster identifies the nucleus as the organelle that stores cellular information. The representation on the poster is consistent with the nucleus’s function (e.g. it is represented as a library, a control tower, or a brain).

TEACHER TIPS

Teachers may differentiate this activity in a number of ways. For students who struggle with the concept of cell structure or function, ask students to include representations of specific organelles.

For more advanced students, identify a specific cell type (e.g. white blood cell, neuron, or for plants, leaf cell or root cell) and require the poster to reflect a representative number of organelles. In other words, a white blood cell would possess more mitochondria than a skin cell because a white blood cell is motile. The white blood cell would also have more lysosomes than the skin cell. A leaf cell would have more chloroplasts than a root cell.

Limit this project to eukaryotic cells. Because prokaryotic cells have fewer organelles than eukaryotic cells, this project is not appropriate for prokaryotic cells.

Extra credit may be awarded if additional functions or organelles are assigned.

CELLS AND CELL SIZE.

1. Consider other shapes for a cell besides a sphere or a cube. What cell shape might increase the surface area to volume ratio? Explain your reasoning.

2. Based on what you know about surface area/volume ratio, why is it necessary for life that most cells be microscopic?

RUBRIC FOR CELLS AND CELL SIZE

1. Consider other shapes for a cell besides a sphere or a cube. What cell shape might increase the surface area to volume ratio? Explain your reasoning.


Student suggests a shape that increases the SA/V ratio such as sheetlike, tubular, porous, or with extensions. The explanation includes a description of how with all of these, more surfaces are in contact with the environment (i.e. surface area is increased without increasing volume).


Student suggests appropriate shapes without offering an explanation or offering an incorrect explanation or student offers a correct explanation but does not suggest any shapes.


Student does not suggest any shapes and the explanation is incorrect, irrelevant, or missing.

2. Based on what you know about surface area/volume ratio, why is it necessary for life that most cells be microscopic?

Criteria for a correct response (2):

Student states that because nutrients and wastes are exchanged with the environment by diffusion, cells must be microscopic because diffusion would occur too slowly in a larger cell for these exchanges to sustain life.


Student states that cells must be microscopic in order to allow nutrients and wastes to be exchanged with the environment (response does not indicate the slow rate of diffusion) or student states that microscopic cells have a large SA/V ratio but doesn’t state why this is important.


Student states that microscopic cells have a small SA/V ratio with or without further explanation or gives a rationale that is unrelated to SA/V ratio (e.g. small size helps the cells reproduce).

OSMOSIS AND DIFFUSION

1. Mr. Martin was stranded on a desert island. He drank approximately eight cups of ocean water daily. Mr. Martin died within a week. When he was discovered, the cause of death was dehydration (lack of water in his body). Explain how drinking ocean water caused him to dehydrate.

2. Potassium ion (K+1) is found in the blood and in the red blood cells of human beings. In healthy individuals, the concentration of K+1 is higher inside the red blood cells than outside. When a person dies, the concentration of K+1 is the same inside and outside the red blood cells within an hour of death. Explain.

RUBRIC FOR ASSESSMENT—OSMOSIS AND DIFFUSION

1. Mr. Martin was stranded on a desert island. He drank approximately eight cups of ocean water daily. Mr. Martin died within a week. When he was discovered, the cause of death was dehydration (lack of water in his body). Explain how drinking ocean water caused him to dehydrate.


Student states that ocean water has a higher salt concentration than human body cells and that water will diffuse out of the cells from a higher water concentration to a lower water concentration.

(NOTE: 1. students may use terms hypertonic or hypotonic. These terms are not needed for a complete response.

2. if student states that “ocean water has more salt than cells” count this as a complete response.)


Student states that ocean water has a higher salt concentration than human body cells but does not describe the flow of water or student states that salt will enter the cells.


Student states that ocean water will enter the cells and poison them or any other incorrect response.

2. Potassium ion (K+1) is found in the blood and in the red blood cells of human beings. In healthy individuals, the concentration of K+1 is higher inside the red blood cells than outside. When a person dies, the concentration of K+1 is the same inside and outside the red blood cells within an hour of death. Explain.


Student states that the cell uses energy to pump potassium into the cell. When the cells die, potassium ions diffuse out of the cell. Student may use the term “active transport” or refer to the cell using ATP, but these are not required for a complete response.


Student states that potassium ion (K+1) is pumped into the cell, but does not refer to the need for energy or student does not refer to diffusion of K+1 ion out of the cell when the person dies.


Student only refers to simple diffusion of K+1 or any other incorrect response.

MARCH

Topic 13: Regulation and Homeostasis

Standards:


6.1.7. Most multi-cellular animals have a nervous system composed of a brain and specialized cells that conduct signals rapidly through the long cell extensions that make up nerves. The nerve cells communicate with each other by secreting specific molecules (neurotransmitters).


6.1.9. The endocrine system consists of glands which secrete chemical messengers (hormones) that are transported via the circulatory system and act on other body structures.

6.3.1. The endocrine, nervous, and immune systems coordinate and help maintain homeostasis in humans and other organisms.

6.3.2. Multi-cellular animals have nervous systems that generate behavioral responses. These responses result from interactions between organisms of the same species, organisms of different species, and from environmental changes.

6.4.3: Many drugs exert their effects by mimicking or increasing the production or destruction of neurotransmitters.

GLEs:

10.6.j. Recognize that as a result of the coordinated structures and functions of organ systems, the internal environment of the human body remains relatively stable despite changes in the outside environment.

10.6.bb. Illustrate how nerve cells communicate with each other to transmit information from the internal and external environment often resulting in physiological or behavioral responses.

10.6.cc. Draw a schematic to illustrate a positive and negative feedback mechanism that regulates body systems in order to help maintain homeostasis.

10.6.ff: Investigate how drugs can affect neurotransmission.

Assessments:

13. Feedback Loops, questions 1-4.


Regulation and Homeostasis

Nervous System:

Chapter 28.2 pp. 612-617

action potential: change in voltage across a neuron's cell membrane, resulting in transmission of a nerve impulse.

axon: the long extension of a neuron between the dentrites and the synaptic ends along which a nerve impulse travels.

dendrite: the proximal end of a neuron at which a nerve impulse is generated.

depolarization: a change in ion permeability across the membrane along the axon of a neuron which results in transmission of a nerve impulse.

nervous system: the bodily system in animals which allows immediate response to environmental stimuli.

neuron: a specialized cell in animals that makes up the nervous system.

neurotransmitter: a molecule released from synaptic vesicles at the ends of neurons which facilitate specific nerve signals.

resting potential: the voltage across the membrane of a neuron when a nerve impulse is not being transmitted.

stimulus: a signal from the environment which initiates the transmission of a nerve impulse.

synapse: a junction between two neurons through which chemical signals (neurotransmitters) and electrical signals (nerve impulses) are transmitted.

synaptic cleft: the space between the ends of one neuron and the dendrites of another across which neurotransmitters carry the signal for a nerve impulse.

threshold: the minimum level that a stimulus must reach to initiate the transmission of a nerve impulse.

Endocrine System:

Chapter 32.1 pp. 698-700Chapter 32.4 pp. 709-715

endocrine gland: a gland which secretes substances directly into the bloodstream rather than through a duct.

gland: an organ in an animal that secretes a chemical within the body.

hormone: a chemical secreted by one organ (an endocrine gland) which exerts an effect on a different organ.

metabolism: the sum of all chemical processes in an animal that either require or release chemical energy.

negative feedback: a regulatory control exerted by opposing processes in the body whereby one process is reduced by the other. Negative feedback results in an equilibrium state (homeostasis).

regulation: the stimulation or reduction of a process in response to environmental stressors.

secrete: to release a chemical within the body.

steroid: a lipid which functions as a hormone in the human reproductive system as well as in other aspects of metabolism.

target cell: the cell in which a hormone exerts its effect, usually by regulating protein synthesis within that cell.

Drugs affecting the human nervous system:

Chapter 28.6 pp.629-631

addiction: a physiological dependence on a drug by an animal.

central nervous system (CNS): the processing branch of the nervous system, consisting of the brain and spinal cord.

depressant: a drug which reduces transmission of neurotransmitters, usually resulting in slowed nerve transmission.

drug: a chemical which initiates a physiological change in an organism.

hallucinogen: a drug which mimics the effects of certain neurotransmitters, resulting in nerve impulses that are not the result of environmental stimuli (hallucinations).

narcotic: a depressant that induces a deeply relaxed state and a strong reduction of pain.

stimulant: a drug which increases transmission of neurotransmitters, usually resulting in faster nerve transmission, an excited state, and reduction in sleep.

tolerance: the ability of an animal to resist the effects of higher doses of drugs. Tolerance is one of the factors that can lead to addiction.

withdrawal: physiological and psychological aversive symptoms that occur when a drug to which an animal has become addicted to is removed. Withdrawal frequently occurs because the drug has caused the body to produce extra receptors for neurotransmitters (or alternatively, to reduce the number of receptors present).


Activity 14: Staying Alive: (Standards: 6.3.1, 6.3.2GLEs: 10.6.bb)


Become familiar with the functions of the nervous system.

Become familiar with the effects of the endocrine system on the body.

Explore how the nervous and endocrine systems coordinate responses in the body.


In this introductory activity, students will be asked to complete four simple tasks requiring conscious control in order to observe the ability of the brain to handle different kinds of tasks. By completing these tasks, students will realize that other body functions are taking place simultaneously that do NOT require their conscious control. This concept becomes a segue into understanding how the endocrine system works and how both the nervous systems and endocrine system work together to coordinate responses in the human body. Imagery is used to demonstrate the ability of the endocrine system to respond to stimuli. CONTEXT: The concepts that we have been developing and how this activity serves as the ‘next step’ can be explained as follows:

This is the first activity in the last subtopic, called Coordination and Response in Animals, of the Chemical Biology unit. So far, students have learned that energy is required to sustain life, where that energy comes from, and how multicellular organisms store and use that energy at a cellular level. From this point on, students will learn different ways in which the body’s cells work together to perform specific functions as tissues and organ systems. Students are introduced to the idea that regulatory behaviors are occurring within their bodies that they have no conscious awareness or control of. The nervous system and endocrine system are primarily responsible for coordinating these regulatory mechanisms. The activities that follow will allow the student to explore how neurons conduct nerve impulses to send messages to and from the brain, how hormones produced by various glands have specific functions to perform, and how feedback systems work to regulate homeostasis.

Activity 15: The Endocrine System: (Standards: 6.1.9, 6.3.1GLEs: 10.6.j, 10.6.cc)


Look at the role the endocrine system plays in coordination and response within the body.

Identify the glands found in the endocrine system, their locations, the hormones they produce and the actions of each hormone.

Create a flowchart that indicates how positive and negative biological feedback loops work within the body.

ACTIVITY OVERVIEW: A synopsis of this lesson is as follows: In this activity, students will learn about the different glands that make up the endocrine system by being assigned specific endocrine glands to research. They will research which hormones are produced by these glands and how their production is controlled by positive and negative feedback loops. Students should come away with a basic understanding of how the endocrine system works to maintain homeostasis within the human body.

CONTEXT: The concepts that we have been developing and how this activity serves as the ‘next step’ can be explained as follows: Homeostasis is the ability to regulate one’s internal environment, in spite of a changing external environment, in order to maintain conditions suitable for life. In the previous activity, “Staying Alive”, students were merely introduced to the nervous and endocrine systems and their roles in maintaining a stable internal environment. By researching a particular gland and its regulatory role in the human body, students will gain a deeper understanding of how hormones act on body systems individually as well as collectively. Earlier in this unit, students learned that organisms function within a narrow range of temperature and pH. This activity is also designed to further the student’s knowledge of the endocrine system’s role in regulating the internal environment within those narrow ranges by way of negative and positive feedback loops. Students will be learning about the nervous system in more depth in the activities to follow.

Activity 17: Nerve Impulses and How They Work: (Standards: 6.1.2, 6.1.7, 6.1.8GLEs: 10.6.bb)


Explore the structure of a nerve cell.

Learn how neurons carry signals.

Learn how these signals move from one neuron to the next.

ACTIVITY OVERVIEW: A synopsis of this lesson is as follows: In this activity, students are introduced to chemical messengers called neurotransmitters as well as what functions they serve within the nervous system. Students will use the same models they created in “The Domino Effect” to simulate the transmission of a signal from one neuron to another across the gaps between them called synapses. This activity is designed simply to be a visual interpretation of the transmission of a nerve impulse.


In the previous activities, “Staying Alive” and “The Domino Effect”, students were introduced to the part the nervous system plays in regulating and coordinating actions within the human body. Here, students are introduced to the structure and function of the nerve cell, or neuron, and learn how impulses travel from one nerve cell to the next by way of neurotransmitters to carry information to and from the central nervous system. Neurons are specialized cells whose functions are directly related to their unique structures. Because of these unique structures, they neurons are able to carry messages to and from the central nervous system, thus enabling the brain and spinal cord to process incoming impulses, to make decisions, coordinate with other organ systems, and therefore direct complex actions of behavior. In the activity that follows, “Drugs and Neurotransmitters”, students will explore the effects that certain types of drugs can have on the transmission of electrical impulses between neurons.

Activity 18: Drugs and Neurotransmitters (Standards: 6.1.7, 6.3.2, 6.4.3GLEs: 10.6.bb, 10.6.ff)

GOALS: In this lab activity students will

Explore the effects of various drugs on the actions of neurotransmitters.

ACTIVITY OVERVIEW: A synopsis of this lesson follows: In this activity, students will determine the effects of drugs on neurotransmitters. Each group of students will research one drug and its effects on the nervous system and then report out to the rest of the class.

CONTEXT: The concepts that we have been developing and how this activity serves as the "next step" can be explained as follows: Students have learned what nerve cells look like, how neurons carry impulses, and how neurotransmitters are used to relay a message from one neuron to the next. This activity will allow the student to explore how drugs can interfere with the normal function of neurotransmitters. This is the culminating activity for nervous system concepts.

FEEDBACK LOOPS

1. Choose one of the following to draw a flowchart on a poster board or come up with another negative feedback system in science. Be prepared to explain the benefits of

having negative feedback systems.

o Feeling of hunger (or thirst) and fullness o Regulation of human body temperature o The regulation of glucose in our bodies (NOTE: Diabetes is a disease in which

part of the feedback loop doesn't function properly due to a lack of the hormone insulin.)

2. Mr. Carter is a butcher. He has cut his finger. At the end of Mr. Carter’s bleeding finger, structures in the blood called platelets begin to form a small plug to stop the bleeding. These platelets cause chemical changes in the blood which (among other things) activate a protein called thrombin. Active thrombin causes a sturdier clot to form from blood proteins. Thrombin also attracts more platelets until the clot stops the loss of blood from the wound.

Is blood clotting an example of a positive feedback loop or negative feedback loop? Explain.

3. Explain the events necessary for a nerve impulse to travel through the body. Include the neuron parts, (dendrites, axon, synapse), and neurotransmitters in your explanation.

4. When Ashley drinks alcoholic beverages, her reaction time slows, and she is less sensitive than usual to pain. These effects on the nervous system last until the alcohol has been removed from her body (usually within a few hours).

Based on the information given, what effect does alcohol seem to have on Ashley’s neurotransmitters? Explain.

RUBRIC FOR ASSESSMENT—FEEDBACK LOOPS

1. Choose one of the following to draw a flowchart on a poster board or come up with another negative feedback system in science. Be prepared to explain the benefits of having negative feedback systems.

o Feeling of hunger (or thirst) and fullness o Regulation of human body temperature o The regulation of glucose in our bodies (NOTE: Diabetes is a disease in which

part of the feedback loop doesn't function properly due to a lack of the hormone insulin.)


Diagram shows a cyclic flow chart. On either side are the two extremes (hungry vs full, hot vs cold, or high glucose vs low glucose). Arrows point to biological responses that drive the state toward one of the extremes:

full

person eats body digests food

hungry


Student identifies the extremes and the arrows show a cyclic flow, but the regulatory mechanisms are not stated, are unclear, or are incorrect.


Flow chart is not cyclic, or arrows are in the wrong direction or extremes are not indicated, are unclear, or are incorrect.

2. Mr. Carter is a butcher. He has cut his finger. At the end of Mr. Carter’s bleeding finger, structures in the blood called platelets begin to form a small plug to stop the bleeding. These platelets cause chemical changes in the blood which (among other things) activate a protein called thrombin. Active thrombin causes a sturdier clot to form from blood proteins. Thrombin also attracts more platelets until the clot stops the loss of blood from the wound.

Is blood clotting an example of a positive feedback loop or negative feedback loop? Explain.


Student states that clotting is a positive feedback loop. Student identifies that one event (platelets activating thrombin) stimulates another event which intensifies the first (thrombin brings more platelets) to bring about a final product (the clot). Student may include a diagram but this is not required for a complete response.


Student states that clotting is a positive feedback loop. The explanation explains that one event stimulates the other, but not that the second event also intensifies the first.

Criteria for an incorrect respone (0):

Student states that clotting is a positive feedback loop but offers no explanation or that clotting is a negative feedback loop with or without an explanation.

3. Explain the events necessary for a nerve impulse to travel through the body. Include the neuron parts, (dendrites, axon, synapse), and neurotransmitters in your explanation.


Student should indicate in their own words that

a stimulus must be picked up by dendrites, an electrical impulse is passed to the cell body, then to the axon and eventually to the

terminal end fibers. At the terminal end fibers, the electrical impulse becomes a chemical message in the

form of neurotransmitters. The neurotransmitters are released and move across the synapse, and are picked up by

the dendrites of the next neuron, where the chemical signal becomes an electrical impulse once again.


Three of these steps are included in the student’s answer.


Two or fewer of these steps are included in the student’s response.

4. When Ashley drinks alcoholic beverages, her reaction time slows, and she is less sensitive than usual to pain. These effects on the nervous system last until the alcohol has been removed from her body (usually within a few hours).

Based on the information given, what effect does alcohol seem to have on Ashley’s neurotransmitters? Explain.


Response indicates that alcohol seems to slow the transmission of neurotransmitters or to reduce the amount of neurotransmitters released or to destroy neurotransmitters because the transmission of nerve impulses is slower or less intense. (NOTE: there are many possible ways to express this idea of reduced neurotransmitter effect.)


Response meets the first criterion for a complete response (reduced neurotransmitter effect) but does not offer an explanation or explanation is incorrect or inconsistent with reduced neurotransmitter effect.


Response does not indicate that alcohol seems to slow the transmisision of neurotransmitters with or without an explanation.

APRIL

Topic 14: DNA and the Genetic Code

Standards:


1.1.3. Theories in science are well-established explanations of natural phenomena that are supported by many confirmed observations and verified hypotheses. The application of theories allows people to make reasonable predictions. Theories may be amended to become more complete with the introduction of new evidence.

1.1.6. Knowledge and skill from sources other than science are essential to scientific inquiry. These include mathematics, reading, writing, and technology.

1.2.1. The pursuit of science can generate the need for advanced technology. Advanced technology, in turn, can provide the opportunity to pursue new scientific knowledge.

6.1.6. Cells store and use information to guide their functions. DNA molecules in each cell carry coded instructions for synthesizing protein molecules. The protein molecules have important structural and regulatory functions.

6.4.2. The scientific investigation of cellular chemistry enables the biotechnology industry to produce medicines, foods, and other products for the benefit of society.

7.1.1. Hereditary/genetic information in chromosomes is contained in molecules of DNA. Genes are sections of DNA that direct syntheses of specific proteins associated with traits in organisms. These consist of various combinations of four different nucleotides that encode this information through their sequences.

7.1.5. During the cell cycle, DNA of the parent cell replicates and the cell divides into two cells that are identical to the parent. This process is used for growth and repair of body tissues and for asexual reproduction.

7.2.1. Evolution is a change in allelic frequencies of a population over time. The theory of evolution is supported by extensive biochemical, structural, embryological, and fossil evidence.

GLEs:

10.1.b. Design and conduct valid scientific investigations to control all but the testable variable in order to test a specific hypothesis.

10.1.c. Collect accurate and precise data through the selection and use of tools and technologies appropriate to the investigations. Display and organize data through the use of tables, diagrams,

graphs, and other organizers that allow analysis and comparison with known information and allow for replication of results.

10.1.f. Use mathematics, reading, writing and technology when conducting scientific inquiries.

10.7.a Describe the relationship between DNA, genes, chromosomes and proteins.

10.7.b. Explain that a gene is a section of DNA that directs the synthesis of a specific protein associated with a specific trait in an organism.

10.7.d. Demonstrate that when DNA replicates, the complementary strands separate and the old strands serve as a template for the new complementary strands. Recognize that this results in two identical strands of DNA that are exact copies of the original.

Assessments:

14. DNA and the Genetic Code.

Text References/vocabulary:

DNA and the Genetic Code

DNA

Chapter 11.1-11.-3 pp. 226-234

base pairing: the specific hydrogen bonding that occurs in DNA or in DNA/RNA interactions whereby adenine is paired with thymine (or uracil) and guanine is paired with cytosine.

helix: a coiled shape that some proteins and nucleic acids assume as a result of intramolecular hydrogen bonding.

nitrogenous base: one of five compounds found in nucleic acids that contribute to the specificity of the nucleic acid.

nucleic acid: a biological polymer which contains parts of a cell’s genetic code.

nucleotide: a monomer of a nucleic acid, consisting of a 5-carbon sugar (ribose or deoxyribose), a phosphate group, and a nitrogenous base.

purine: a nitrogenous base composed of a double ring molecule. Adenine and guanine are purines.

pyrimidine: a nitrogenous base composed of a single ring molecule. Thymine, cytosine, and uracil are examples of pyrimidines.

replication: the process of a DNA molecule producing an exact copy of itself through cellular processes.

template: a single strand of DNA upon which a complementary strand of DNA or a strand of RNA is copied.

transforming factor: in early work in molecular genetics, transforming factor was a substance produced by one cell that had the ability to change the characteristics of other cells.

Protein synthesis

Chapter 11.4-11.5 pp. 235-241

anticodon: in tRNA, a triplet of nitrogenous bases that is complementary to a specific codon in mRNA.

codon: in mRNA, a triplet of nitrogenous bases that corresponds to a specific amino acid or stop signal.

genetic code: the one-to-one correspondence of each codon to a specific amino acid or stop signal. Although each codon corresponds to only one amino acid or stop signal, most of the amino acids are coded for by more than one codon.

messenger RNA (mRNA): RNA molecule that is translated (by ribosomes) into an amino acid sequence.

polypeptide: a polymer of amino acids. A functional polypeptide is a protein.

RNA: a nucleic acid produced from a DNA template that is directly involved with some aspect of protein synthesis in cells.

stop codon: a codon which does not correspond to an amino acid during translation. Stop codons give the signal to the ribosome to end translation. The three stop codons are UGA, UAG, and UAA.

transcription (transcribe): a process by which a DNA template is used to produce a single-stranded RNA molecule.

transfer RNA (tRNA): an RNA molecule that transports amino acids to the ribosome and carries the growing polypeptide within the ribosome. A cell may contain 61 tRNA types, each with a different anticodon.

translation: the process in which a ribosome travels down a strand of mRNA and creates a polypeptide with a specific amino acid sequence as determined by the sequence of nitrogenous bases on the mRNA.


Activity 1: DNA Extraction.(Standards 1.1.1, 1.1.3, 1.1.6, 1.2.1, 6.1.6, 6.4.2, 7.1.1GLEs: 10.1.b, 10.1.c, 10.1.f, 10.7.b)

GOALS: In this activity, students will be able to

extract DNA from a variety of organisms. make comparisons between the extracted DNA samples.


Students extract and spool DNA from a variety of organisms and learn that DNA is readily observable in large amounts in a diversity of organisms.

CONTEXT: the concepts we have been developing and how this activity serves as the next step can be explained as follows:

Students have come out of Chemical Biology with learning about regulation of behavior in individual organisms. The final unit, genetics, begins with regulation of the inheritance of the structures discussed so far. The discussion of the cell did not address DNA or the nucleus directly. This activity addresses this concept first by showing students approximately how much DNA is present in cells. It also introduces the practice of biotechnology--how do we study DNA? First we have to extract it.

Activity 2: DNA Structure and the Genetic Code(Standards 6.1.6, 7.1.1., 7.1.5GLEs: 10.7.a, 10.7.b)

GOALS: In this lab activity students will be able to

describe the structure of DNA. explain how the sequence of nucleotides in DNA is related to its function of providing coded

genetic information.


Using 2-dimensional models, students construct a segment of a DNA molecule consisting of 6 paired nucleotides. During the manipulation part of the activity and review and analysis section, students answer questions about the structure of DNA, base pairing and the relationship between DNA’s structure and encoded genetic information.

CONTEXT: the concepts we have been developing and the way this activity serves as the next step can be explained as follows:

This activity provides hands-on illustration of the important aspects of DNA structure. It shows them the double helix configuration of DNA, and also emphasizes the base pairing of Adenine to Thymine and Guanine to Cytosine (Chargraff's rule). This structure is crucial in understanding how protein synthesis occurs and the role of mutations on genetic expression.

Activity 3: DNA replication and the Cell Cycle

GOALS: in this lab activity students will be able to

use models to describe how DNA replicates forming identical copies of itself. explain the importance of DNA replication in the cell cycle and the life of an organism


This activity begins with an overview of the phases of the cell cycle and then focuses on the events that occur during the S (DNA synthesis) phase of the cycle. Students use 2-dimensional models of DNA to simulate DNA replication by first splitting the molecules at weak hydrogen bonds where the bases join and then by pairing each unpaired nucleotide with its complementary nucleotide. During the manipulation part of the activity and later during the review and analysis section, students compare the original DNA nucleotide sequence with the sequence in the DNA replicates, and they explain the importance of DNA replication in the cell cycle and the life of the organism.

CONTEXT: the concepts we have been developing and how this activity serves as the next step can be described as follows:

Although this activity introduces the cell cycle, it is still focused largely on DNA. The feature of DNA that makes it our genetic material is that it can be copied exactly by cellular process. The important concept to address here is that every reproducing cell in an organism has the same nucleotide sequence of DNA because of DNA replication. This activity will be revisited when the students learn about mitosis and cancer.

Activity 4: Protein Synthesis.(Standards: 7.1.1, 7.1.3, 7.2.1GLEs: 10.7.a, 10.7.b, 10.7.c, 10.7.e)

GOALS: In this lab activity students will be able to:

describe how the genetic code in DNA is transcribed into RNA and translated into proteins. explain how differences in the DNA code can result in the assembly of different kinds of proteins

which are responsible for traits in an organism.


Using 2-dimensional puzzle pieces, students model the process of protein synthesis. First, students build a 12 unpaired nucleotide sequence of a sense strand of DNA. This DNA strand is used as a template for transcribing mRNA. Students then place the mRNA strand on a drawing of a ribosome where they model the steps in which tRNA and enzymes connect amino acids in a particular order to make a protein. Finally, using the terms DNA, mRNA, tRNA, ribosome, nucleus, amino acid, codon, transcription, and translation, students describe how proteins are made in cells. Teachers should note that the process whereby DNA is transcribed into RNA and then translated into proteins which are associated with traits is known as the central dogma of molecular biology.


This activity culminates the DNA/RNA/protein synthesis activities using the same DNA puzzles. Activities 2, 3, and 4 may be blended according to the needs of the class. Students need to remember that DNA is present throughout the cell cycle, but RNA and proteins are only made as needed. This activity also leads into the study of mutations. Mutations are the next logical topic of study because they are a result

of DNA changes, they can lead to cell death or cancer (as discussed next0, or they can lead to adaptations which are passed through the genome (evolution).

Topic 15: Cell Cycle and Cancer

Standards:

6.4.1. Certain chemicals, pathogens, and high-energy radiation seriously impair normal cell functions and the health of the organism.

7.1.3. Mutations in DNA of organisms normally occur spontaneously at low rates, but can occur at higher rates (i.e., exposure to pathogens, radiation and some chemicals). Most mutations have no effect on the organism, but some may be beneficial or harmful depending on the environment.

7.1.4. Only random mutations in germ cells (gametes) can create the variation that is inherited by an organism’s offspring. Somatic mutations are not inherited, but may lead to cell death, uncontrolled cell growth, or cancer.

7.1.5 During the cell cycle, DNA of the parent cell replicates and the cell divides into two cells that are identical to the parent. This process is used for growth and repair of body tissues and for asexual reproduction.

7.1.9 Embryological development in plants and animals involves a series of orderly changes in which cells divide and differentiate. Development is controlled by genes whose expression is influenced by internal factors (i.e., hormones) and may also be influenced by environmental factors (i.e., nutrition, alcohol, radiation, drugs, and pathogens). Alteration in this balance may interfere with normal growth and development.

GLEs:

10.7.i. Describe how exposure to radiation, chemicals and pathogens can increase mutations 10.7.k. Explain that mutations in the DNA sequence of a gene may or may not affect the expression of

the gene. Recognize that mutations may be harmful, beneficial, or have no impact on the survival of the organism.

10.7.l Explain how the type of cell (gamete or somatic) in which a mutation occurs determines heritability of the mutation. Predict the possible consequences of a somatic cell mutation.

10.7.m. Explain how the cell cycle contributes to reproduction and maintenance of the cell and/or organism.

10.7.n. Recognize that during the formation of gametes, or sex cells (meiosis), the number of chromosomes is reduced by one half, so that when fertilization occurs the diploid number is restored.

10.7.p. Compare and contrast the processes of growth (cell division) and development (differentiation).

10.7.q, Recognize that any environmental factor that influences gene expression or alteration in hormonal balance may have an impact on development.

Assessments:

15. Cell Cycle and Cancer, questions 1-4.


Cell Cycle and Cancer

Chapter 9.2-9.4 pp. 182-191

benign: referring to a tumor, a non-spreading mass of abnormal cells.

cancer: a pathological condition where cell reproduction is occurring in a rapid uncontrolled manner.

cell cycle: the sequence of events that occur to a cell from the time the cell first forms until the cell reproduces.

cell division: a process in which a cell produces a duplicate copy of itself.

centromere: a structure on a chromosome of a eukaryotic cell which forms a juncture of the chromatids. The centromere attaches to the spindle fiber during metaphase of cell division.

chemotherapy: a treatment for cancer which involves administering drugs to a patient which attack cells undergoing rapid cell division.

chromatid: one of two strands in a chromosome. The chromatids carry DNA, and during cell division, each daughter cell receives one chromatid from each chromosome.

chromatin: the nuclear material consisting of nucleic acids and proteins. Chromatin is not organized into chromosomes, and is present when mitosis or meiosis is not occurring.

chromosome: an organizational unit of genetic material in eukaryotic cells. Chromosomes are composed of proteins and nucleic acids.

cytokinesis: segregation of cytoplasm at the end of cell division.

daughter cell: one of two resulting cells from cell division. In mitosis, each daughter cell contains an exact copy of the genetic material from the parent cell. In meiosis, each daughter cell contains one half the genetic material from the parent cell.

malignant: referring to a tumor, a mass of cells which has spread beyond a central location. Malignant tumors are often called cancers.

metastasis: the spreading of cancer cells from a central location to other parts of the body. Metastasis is associated with progression of the cancer.

mitosis: process in cell division of eukaryotic cells whereby the parent cell’s chromosomes are evenly distributed to two daughter cells.

radiation therapy: a treatment for cancer in which the patient is exposed to ionizing radiation. Usually, the specific location of abnormal cells is exposed to the radiation in order to interrupt the rapid rate of mitosis.

spindle: a framework of microtubules that guide the movement of chromosomes during mitosis and meiosis.

tumor: a mass of abnormal cells in a central location with the potential to engage in rapid uncontrolled mitosis.


Activity 5: Cancer and the Cell Cycle(Standards: 6.4.1, 7.1.3, 7.1.4GLEs: 10.7.i, 10.7.k, 10.7.q)

GOALS: in this lab activity, the student will be able to

understand that a variety of factors can cause cancer. understand that cancer represents a breakdown of the normal processes that regulate the cell

cycle. be able to explain that cancer is associated with damage to genes involved in the regulation of

the cell cycle.


“Cancer and the Cell Cycle” and “The Faces of Cancer” are included in the Genetics/Biotechnology Unit to enable students to apply their knowledge of the cell cycle to understanding cancer. Specifically, in “Cancer and the Cell Cycle” students view CD-ROM videos and animations to help them construct an explanation for how cancer develops, then use their new understanding to explain several historical observations about agents that cause cancer. The “Cancer and the Cell Cycle” student activity was modified from an activity by the same name from Cell Biology and Cancer, NIH Curriculum Supplement, Grades 9-12, 1999.

CONTEXT: the concepts we are developing and how this activity serves as the next step can be

explained as follows:

This activity bridges the discussion of DNA and mutations to the discussion of the cell cycle, cell reproduction, and why damage to one cell may have harmful effects to the organism in general. This unit also focuses on risk factors for cancer, and why they are risk factors, so that students are better prepared to make informed decisions about their health and lifestyle choices.

Activity 6: Mitosis and the Cell Cycle(Standards: 7.1.5, 7.1.9GLEs: 10.7.j, 10.7.l, 10.7.n, 10.7.p)

GOALS: In this activity students will

describe the sequence of events that occur during the cell cycle that involve chromosome replication and the distribution of replicated chromosomes to daughter cells.

explain the significance of each new daughter cell receiving the same amount and kind of chromosomes present in the parent cell.


In this activity students use models of chromosomes made from beads and pieces of yarn and chenille stems and outline drawings of cells to investigate the replication of chromosomes and their distribution to daughter cells during the cell cycle. Specifically, students model the G1, S and M phases of the cell cycle in an animal cell for 2 pair of chromosomes by placing the chromosome models on seven outline drawings of cells that illustrate different stages in the phases. Following this manipulation activity, students compare the number and kind of chromosomes in the parent cell with the number and kind in the daughter cells. They also draw some conclusions about the importance of these phases of the cell cycle in providing genetic continuity between cell generations.


This is an activity that illustrates the phases of mitosis, emphasizing the concept of diploid number. The important concept here is for students to realize that the number of chromosomes is preserved in mitosis, not the names and appearances of each phase. This is a logical next step after discussing DNA replication but before discussing meiosis and genetics.

Topic 16: Meiosis and Chromosomes

Standards:

1.1.4. Understand that: Investigating most real-world problems requires building upon previous scientific findings and cooperation among individuals with knowledge and expertise from a variety of scientific fields. The results of scientific studies are considered valid when subjected to critical review where contradictions are resolved and the explanation is confirmed.

1.2.1. The pursuit of science can generate the need for advanced technology. Advanced technology, in turn, can provide the opportunity to pursue new scientific knowledge.

1.2.2. The social, economic, and political forces of a society have a significant influence on what science and technology programs are pursued, funded, and implemented.

7.1.6 Meiosis is the production of sex cells (gametes). The production and release of these gametes is controlled by hormones. In meiosis, the number of chromosomes is reduced by one-half and chromosomes may randomly exchange homologous parts to create new chromosomes with combinations not necessarily found in the parent cell. This may increase variation within the species.

7.1.7. Upon fertilization, the fusion of the gametes restores the original chromosome number, and new gene combinations lead to increased genetic variation, which, in turn, increases the likelihood of survival of the species.

7.1.8. The sex chromosomes contain different genes, and therefore, certain traits will show patterns of inheritance based on gender.

7.3.1. The expanding ability to manipulate genetic material, reproductive processes, and embryological development creates choices that raise ethical, legal, social, and public policy questions.

GLEs:

10.7.g. Analyze a karyotype to determine chromosome numbers and pairs. Compare and contrast normal and abnormal karyotypes.

10.7.h. Explain how crossing over and Mendel’s Laws of Segregation and Independent Assortment contribute to genetic variation in sexually reproducing organisms.

10.7.l Explain how the type of cell (gamete or somatic) in which a mutation occurs determines heritability of the mutation. Predict the possible consequences of a somatic cell mutation.

10.7.n. Recognize that during the formation of gametes, or sex cells (meiosis), the number of chromosomes is reduced by one half, so that when fertilization occurs the diploid number is restored.

10.7.o. Explain why sex-linked traits are expressed more frequently in males.

10.7.hh Discuss examples of how genetic engineering technology can be applied in biology, agriculture and medicine in order to meet human wants and needs.

Assessments:

16. Meiosis and Chromosomes, questions 1-3.


Meiosis and Chromosomes

Chapter 9.5-9.6 pp. 192-201Chapter 10.4 pp. 218-219

crossing over: exchange of genetic material between homologous chromosomes during prophase I of meiosis.

diploid: having two homologous sets of chromosomes.

fertilization: fusion of the nuclei of a male and a female gamete to create a diploid zygote.

gamete: a haploid sex cell. The male gamete is a spermatozoan (sperm) and a female gamete is an egg.

generation: in genetics, all offspring resulting from sexual reproduction between two parents.

genetic linkage: tendency for alleles of genes on the same chromosome to be inherited together.

genetic variation: differences between individuals in a population related to the allelic frequency within that population.

haploid: having one copy of each chromosome pair. Sex cells are haploid at the end of meiosis 2.

homologous chromosomes: a matching pair of chromosomes, one inherited from each parent. Homologous chromosomes appear identical microscopically.

karyotype: display of a person's chromosomes from the body cells.

meiosis: a type of cell division occurring in sex cells that produces four cells, each with half as many chromosomes as the parent cell

sex cell: the cells produced by the ovaries (female) and testes (male) involved in sexual reproduction.


Activity 7: Meiosis and Genetic Variation(Standards: 7.1.6, 7.1.7, 7.1.8GLEs: 10.7.h, 10.7.l, 10.7.n, 10.7.o)

GOALS: in this lab activity students will be able to

summarize the events that reduce the chromosome number from diploid to haploid in the formation of gametes during the sexual life cycle.

describe how independent assortment and crossing over that occur during meiosis produce a variety of genetic combinations in offspring.

explain the importance of the genetic variation that results from meiosis.


In this activity students use models of chromosomes made from beads and pieces of yarn and chenille stems and outline drawings of cells to investigate events that occur during the meiosis phase of the sexual life cycle. Specifically, students model reduction division (diploid to haploid), independent assortment, and crossing over. Following the manipulation part of the activity, students use data they have collected to answer a series of questions about the process of meiosis and its importance in producing genetic variation among offspring.

CONTEXT: the concepts we are developing and the way this activity serves as the next step can be explained as follows:

This activity uses the same manipulatives in "Mitosis and the Cell Cycle" to illustrate the reduction in chromosome number that occurs in meiosis. Meiosis is responsible for producing gametes, and thus it sets the stage for discussing genetic inheritance.

Activity 8: Chromosome Testing (this activity is linked to SchoolNet)(Standards: 1.1.4, 1.2.1, 1.2.2, 7.1.6, 7.1.7, 7.1.8, 7.1.9, 7.3.1GLEs: 10.7.g, 10.7.n, 10.7.hh)

GOALS: In this lab activity students will

Analyze a human karyotype in terms of chromosome numbers, sex of the individual, and chromosome abnormalities.

Simulate a decision-making process given information about karyotype of a developing fetus.


Students work in groups of 2 to develop a scenario where a baby is expected. When the scenario is approved, the group each receives two envelopes, each containing 23 chromosomes. One envelope corresponds to the egg, the other corresponds to the sperm. Students create a karyotype using a listing of human chromosomes. Students determine 1) the sex of the child and 2) whether the child has a chromosomal abnormality. If the child has a chromosomal abnormality, students read an excerpt describing the clinical manifestations of the abnormality. To conclude the activity, student groups describe the decisions and obstacles ahead for the characters in the scenario they have created.


Students relate errors in chromosomal numbers during meiosis (nondisjunction) to the effects that would appear in a child. This activity combines the science of chromosomal genetics with the social aspect of how real men and women have to deal with situations like this. This activity shows students that genetics and science in general are human endeavors, and that non-scientists must make decisions based on the findings of science.

DNA and the Genetic Code

The Goldstein family is of Ashkenazi Jewish descent and recently experienced the tragic death of their youngest child, Sarah, who was diagnosed with Tay Sachs disease. Tay Sachs is a genetic disorder resulting from a mutation on chromosome 15. This mutation causes a fatty substance to build up in the nerve cells of the brain, resulting in a deterioration of brain function that ultimately leads to paralysis and eath before the age of 5. A person with Tay Sachs disease lacks a protein (enzyme) called hexosaminidase A, which is necessary for breaking down certain fatty substances.

After Sarah’s death, the family decides to consult a genetic counselor to better understand the implications for the rest of the family. The genetic counselor recommended that the entire family be tested for Tay Sachs.

Figure 1: Genetic Testing ResultsDNA Sequence on Chromosome 15

Siblings First Allele Second Allele AgeMichael AGACTATCA AGACTACCA 18Jennifer AGACTACCA AGACTACCA 12Bob AGACTACCA AGACTACCA 7Sarah AGACTATCA AGACTATCA Died – age 3

1. The genetic screening for Tay Sachs provided the evidence in Figure 1

a. Circle the specific mutations in the DNA sequence (Figure 1) that are responsible for Sarah’s disorder.

2. In the process of transcription, DNA is copied into mRNA.

a. Identify the messenger RNA strand that is transcribed from Sarah’s DNA sequence.

Identify the messenger RNA strand that is transcribed from Jennifer’s DNA sequence.

b. Describe the sequence of events that resulted in Sarah’s inability to break down fatty substances in the brain (Tay Sachs).

RUBRIC DNA AND THE GENETIC CODE

1. The genetic screening for Tay Sachs provided the evidence in Figures 1 and 2.

a. Circle the specific mutations in the DNA sequence (Figure 1) that are responsible for Sarah’s disorder.

Criterion for a complete response (2):

Student circles the seventh base on Sarah’s first and second allele.


Student circles only one mutation.


Student circles the incorrect bases or circles no bases.

2. In the process of transcription, DNA is copied into mRNA.

a. Identify the messenger RNA strand that is transcribed from Sarah’s DNA sequence.

Identify the messenger RNA strand that is transcribed from Jennifer’s DNA sequence.


Students’ response must include

a. Sarah’s mRNA would be UCUGAUAGUb. Jennifer’s mRNA would be UCUGAUGGU


One of the sequences is correct or both sequences are correct, except that T is included instead of U.


Both sequences are incorrect or student has copied the DNA sequences, replacing the T with U.

c. Describe the sequence of events that resulted in Sarah’s inability to break down fatty substances in the brain (Tay Sachs).


Students’ response must include:a. Different nucleotide sequence results in a change in the amino acid

b. Different amino acid results in a change in the proteinc. Different protein is unable to carry out its intended function

NOTE: Student may include a change in mRNA sequence, but this is not required for a complete response.


Includes two of the criteria listed in a complete response or includes one criterion and mentions a change in mRNA in the correct sequence.


Mentions fewer than two of the criteria and does not mention a change in mRNA.

THE CELL CYCLE AND CANCER

1. Why is it necessary for the cell’s DNA to replicate prior to cell division and mitosis?

High energy electromagnetic radiation (X rays) are known to cause mutations in DNA and thereby cause cell death and cancer.

2. Describe one mechanism by which mutations caused by X-rays can cause cancer (i.e. uncontrolled cell growth)

3. Women who are pregnant are not given X rays because of the risk of cell death to the developing fetus (baby). Why is the danger of cell death by X rays greater for a developing fetus than for an adult?

4. Despite the fact that high energy radiation may cause cancer, this type of radiation is also used to treat cancer once it has developed. Explain why.

RUBRIC FOR THE CELL CYCLE AND CANCER

1. Why is it necessary for the cell’s DNA to replicate prior to cell division and mitosis?


Student states that this is necessary so that the daughter cells will have an exact copy of the parent cell’s DNA.


Student states that this is necessary so that the daughter cells will be exactly like the parent cell but does not mention DNA.


Student confuses DNA replication with mitosis, indicating an understanding that they are the same (they aren’t).

High energy electromagnetic radiation (X rays) are known to cause mutations 8in DNA and thereby cause cell death and cancer.

2. Describe one mechanism by which mutations caused by X rays can cause cancer (i.e. uncontrolled cell growth)


Student states that X rays can cause a stop codon to be eliminated, resulting in a new amino acid structure or that the mutation can alter a regulatory protein which would ordinarily inhibit cell division.


Student states that X rays can stimulate cell division, but doesn’t explain how.


Student states that X rays can kill cells. While this statement is correct, it does not address how mutations from X rays may cause cancer.

MEIOSIS AND CHROMOSOMES

1. Mr. and Mrs. Anderson have 46 chromosomes in all of their body cells. Explain how the production of sex cells (meiosis) ensures that the Anderson’s new baby (Jolene) will also

have 46 chromosomes in her body cells (NOTE: assume “body cells” do not include the “sex cells.”)

2. Jolene is Mr. and Mrs. Anderson’s third baby. They also have a son (Victor) and another daughter (Nikki).

Mr. Anderson’s physical description: blond hairblue eyesattached earlobeslight colored skinhair in his ears

Mrs. Anderson’s physical description: brown hairbrown eyesunattached earlobesdark colored skinno hair in her ears

Victor Anderson’s physical description: brown hairblue eyesunattached earlobeslight colored skinhair in his ears

Nikki Anderson’s physical description: brown hairbrown eyesattached earlobesdark colored skin (not as dark as her mother’s)

no hair in her ears

Jolene Anderson’s physical description: blond hairbrown eyesunattached earlobeslight colored skinno hair in her ears

2, All three of the children have physical characteristics in common with both parents. Nevertheless, none of the children looks exactly like either parent nor do they look exactly like one another. Explain why no child looks like any other family member in terms of chromosomes.

3. The trait for hair in the ears is carried only on the Y chromosome. If the Andersons have another child, what is the probability of the child having hair in the ears if it’s a boy? What is the probability if the child is a girl? Explain.

RUBRIC FOR MEIOSIS AND CHROMOSOMES

1. Mr. and Mrs. Anderson have 46 chromosomes in all of their body cells. Explain how the production of sex cells (meiosis) ensures that the Anderson’s new baby (Jolene) will also

have 46 chromosomes in her body cells (NOTE: assume “body cells” do not include the “sex cells.”)


Student states that in meiosis, the sex cells (student may call these “eggs” and “sperm” although this is not necessary) each have one half the number of chromosomes as the body cells. When the sex cells combine during fertilization, the fertilized egg has 46 chromosomes.


Student states that Jolene gets half of her chromosomes from each parent but does not mention how meiosis ensures this.


Student states that the egg and sperm combine to form a zygote, fertilized egg, or baby, but does not mention the role of chromosomes or meiosis.

2. All three of the children have physical characteristics in common with both parents. Nevertheless, none of the children looks exactly like either parent nor do they look exactly like one another. Explain why no child looks like any other family member in terms of chromosomes.


Student states that none of the children will look exactly like either parent because each child gets two copies of each chromosome from each parent. The children each look different from one another because the chromosomes each parent contributes is random. Therefore, each child receives a different combination of chromosomes from each parent.


Student correctly explains why the children don’t look exactly like either parent or correctly explains why none of the children look exactly like one another, but does not correctly explain both.


Student relates the children’s appearances to dominance or recessiveness of the various physical traits.

3. The trait for hair in the ears is carried only on the Y chromosome. If the Andersons have another child, what is the probability of the child having hair in the ears if it’s a boy? What is the probability if the child is a girl? Explain.

Criteria for a correct response (2):

Student states that if the child is a boy, there is a 100 % chance of hairy ears. If the child is a girl, there is 0 % chance. Boys have one Y chromosome and girls do not have a Y

chromosome. If a gene is on the Y chromosome, it will be present in males and be absent from females.


Student gives the correct probabilities or gives a correct explanation as described above but does not give both.


Student gives an incorrect probability and gives an incorrect explanation (or no explanation).

MAY

Topic 17: Genetics

Standards:


1.1.2. Science is distinguished from other ways of knowing by the use of empirical observations, experimental evidence, logical arguments and healthy skepticism.

1.1.4. Investigating most real-world problems requires building upon previous scientific findings and cooperation among individuals with knowledge and expertise from a variety of scientific fields. The results of scientific studies are considered valid when subjected to critical review where contradictions are resolved and the explanation is confirmed

1.1.5. In communicating and defending the results of scientific inquiry, arguments must be logical and demonstrate connections between natural phenomena, investigations, and the historical body of scientific knowledge.

1.3.1. New disciplines of science emerge as older disciplines interface into an integrated study of the natural world. As the body of scientific knowledge grows, the boundaries between individual disciplines diminish.

7.1.1. Hereditary/genetic information in chromosomes is contained in molecules of DNA. Genes are sections of DNA that direct syntheses of specific proteins associated with traits in organisms. These consist of various combinations of four different nucleotides that encode this information through their sequences.

7.1.2. Known patterns of inheritance can be used to make predictions about genetic variation.

7.3.1. The expanding ability to manipulate genetic material, reproductive processes, and embryological development creates choices that raise ethical, legal, social, and public policy questions.

7.3.2. Recombinant DNA technology, which is a form of genetic engineering, involves the insertion of DNA from one cell into a cell of a different organism where the inserted DNA is expressed. Genetic engineering is being applied in biology, agriculture, and medicine in order to meet human wants and needs.

7.3.3. DNA is analyzed to determine evolutionary relationships, study populations, identify individuals, and diagnose genetic disorders.

GLEs:

10.1.a Identify and form questions that generate a specific testable hypothesis that guide the design and breadth of the scientific investigation.

10.1.b Design and conduct valid scientific investigations to control all but the testable variable in order to test a specific hypothesis.

10.1.c Collect accurate and precise data through the selection and use of tools and technologies appropriate to the investigations. Display and organize data through the use of tables, diagrams, graphs, and other organizers that allow analysis and comparison with known information and allow for replication of results.

10.1.d Construct logical scientific explanations and present arguments which defend proposed explanations through the use of closely examined evidence.

10.1.e. Communicate and defend the results of scientific investigations using logical arguments and connections with the known body of scientific information.

10.6.ee. Investigate how scientists use biotechnology to produce more nutritious food, more effective medicine, and new ways to mitigate pollution.

10.7a Describe the relationship between DNA, genes, chromosomes and proteins.

10.7.e. Illustrate how a sequence of DNA nucleotides codes for a specific sequence of amino acids.

10.7.f. Use Punnett squares, including dihybrid crosses, and pedigree charts to determine probabilities and patterns of inheritance (i.e., dominant/recessive, co-dominance, sex-linkage, multi-allele inheritance).

10.7.ff Explain how DNA evidence can be used to determine evolutionary relationships.

10.7.gg Investigate how the human ability to manipulate genetic material and reproductive processes can be applied to many areas of medicine, biology, and agriculture. Evaluate the risks and benefits of various ethical, social and legal scenarios that arise from this ability.

10.7.hh. Discuss examples of how genetic engineering technology can be applied in biology, agriculture and medicine in order to meet human wants and needs.

Assessments:

17. Genetics, questions 1,2, 3a, 3b, 4.


Genetics

Mendelian Inheritance

Chapter 10.1-10.2 pp. 206-213

cross: in genetics, a mating between two organisms resulting in offspring.

dihybrid cross: a cross in which the distribution of two genes is followed.

dominant: an allele that is expressed in the homozygous or heterozygous state.

genetics: scientific study of inheritance of traits from one organism to another through DNA.

genotype: a description of the alleles in an individual that affect expression of a gene or genes.

heterozygous: A genotype in which an individual possesses the dominant and recessive allele of a gene.

homozygous: A genotype in which an individual possesses either two dominant alleles or two recessive alleles of a gene.

hybrid: offspring of two different true-breeding varieties

inheritance: in genetics, the transfer of genetic material from parents to offspring.

monohybrid cross: a cross in which the distribution of a single gene is followed.

phenotype: a description of the physical appearance of an organism as it is affected by the alleles of a gene the organism possesses.

principle of segregation: a hypothesis that suggests that pairs of alleles separate during gamete formation.

Punnett Square: a graphic organizer used to determine the possible genotypes in offspring from a cross and their relative probabilities.

recessive: an allele that is only expressed in the homozygous state.

trait: a physical characteristic.

Variations of Inheritance Patterns

Chapter 10.3 pp. 215-217 Chapter 14.5 pp. 317-318Chapter 10.5 pp. 220-221

codominance: a situation where a trait is controlled by two dominant alleles and a recessive allele. If both dominant alleles are present, they are both expressed equally. The ABO blood type phenotype is an example of codominance.

blood type: a classification based on expression of alleles as surface antigens on red blood cells.

polygenic inheritance: a situation where a trait is under the genetic control of several genes. Examples in humans include height and skin color.

sex linked gene: a gene that is located on the sex chromosomes. Usually this term refers to X linkage. Sex linked genes are expressed differently in males and females.

Biotechnology

Chapter 13 (all) pp. 266-285

biotechnology: use of organisms to perform practical tasks. Usually this refers to genetic manipulation of the organisms.

clone: an organism with the identical genetic makeup of another organism.

differentiation: in biology, the process by which a cell or group of cells assumes unique structures and functions.

gel electrophoresis: a procedure in biotechnology where macromolecules (DNA, RNA, or proteins) are separated by molar mass in a gel matrix exposed to an electric field.

genetic marker: specific portion of DNA that varies among individuals that may be used in biotechnology for classification or diagnosis.

genetically modified organism: an organism whose genome has been artificially altered by mutation or by introduction of exogenous DNA.

genome: the complete set of an organism’s genetic material.

plasmid: circular piece of DNA found in bacteria that is separate from the bacterial chromosome. Plasmids may contain genes and may be introduced through natural processes or artificially.

polymerase chain reaction: a technique in biotechnology where a segment of DNA is replicated artificially to produce large quantities of identical DNA without using living cells.

recombinant DNA: a branch of biotechnology in which DNA from different sources are combined in a single organism.

restriction enzyme: an enzyme that cuts the sugar-phosphate “backbone” of DNA between specific nucleotides. Also called a restriction endonuclease.

stem cell: an undifferentiated cell that can be artificially stimulated to differentiate into a specific function.

“sticky end”: specific single stranded nucleotide sequences at the ends of DNA molecules that have been exposed to restriction enzymes. Sticky ends can create base pairs with other complementary sticky ends of other DNA molecules, thus creating DNA with desired base pair sequences. This technique of exposing DNA molecules to restriction enzymes, then recombining them with other DNA fragments is sometimes called gene splicing.

transgenic: genetically modified organism whose source of new genetic material is a different species.

Suggested activities:

Activity 9: Mystery of the Crooked Cell GOALS: in this lab activity the student will be able to

Determine the Mendelian inheritance pattern of sickle cell anemia. Correlate the inheritance pattern (homozygous and heterozygous genotypes) with

symptoms of affected individuals. Use gel electrophoresis to separate simulated DNA strands. Use the results of gel electrophoresis to identify individuals who are carriers of sickle cell

trait, who do not have the trait, and who can develop the disease. Predict the probability of passing sickle cell anemia from carrier parents (and affected

parents) to their children.

ACTIVITY OVERVIEW: a synopsis of this activity follows: In this extensive lab activity, students use simulated blood samples and gel electrophoresis to

diagnose members of a hypothetical family for sickle cell anemia. Students also conduct a simulation activity with bean seeds to model how selective forces can change allele frequencies in a population.

CONTEXT: the concepts we have been developing and the way this activity serves as the next step can be explained as follows:

This activity combines the principles of Mendelian genetics with a powerful tool in biotechnology. Students have learned about monohybrid crosses (with Punnett Squares) in seventh grade Our Genes Ourselves. This activity takes that understanding to the molecular level. Students ask "what do 'dominant' and 'recessive' mean at the level of DNA?" This unit should also be supplemented with genetics problems that illustrate co-dominance (blood typing), sex linked traits (color blindness or hemophilia) and other variants of Mendelian inheritance pattern. The Coalition unit Genetics and Biotechnology offers several supplemental activities to teach these concepts.

For additional biotechnology practice, the pGLO activity is recommended. In this activity, students culture E. coli, then using CaCl2 to make their cell membranes permeable, transform the bacteria with DNA coding for bioluminescence (DNA is obtained from jellyfish). This activity will satisfy standard 7.3.2 for understanding genetic engineering practices.

GENETICS

The Goldstein family is of Ashkenazi Jewish descent and recently experienced the tragic death of their youngest child, Sarah, who was diagnosed with Tay Sachs disease. Tay Sachs is a genetic disorder resulting from a mutation on chromosome 15. This mutation causes a fatty substance to build up in the nerve cells of the brain, resulting in a deterioration of brain function that ultimately leads to paralysis and death before the age of 5. A person with Tay Sachs disease lacks a protein (enzyme) called hexosaminidase A, which is necessary for breaking down certain fatty substances.

After Sarah’s death, the family decides to consult a genetic counselor to better understand the implications for the rest of the family. The genetic counselor recommended that the entire family be tested for Tay Sachs.

Figure 2 Family Pedigree

1. Identify the autosomal pattern of inheritance in which Tay Sachs is passed from one generation to the next using the evidence in Figure 2. Explain your reasoning.

2. Identify both Mom and Dad’s genotypes based on the information provided in Figures 1 and 2 and in the family history.

Mom ________________ Dad ________________

3. Years later, Michael (Sarah’s oldest brother) and his new bride, Rebecca, began to plan for a

family. Rebecca was tested for the presence of the Tay Sachs mutation because of Michael’s

family history.

b. Predict the probability of each genotype and phenotype in the offspring if Rebecca IS

carrying a mutation for Tay Sachs.

Probability Genotype Phenotype

c. Predict the probability of each genotype and phenotype in the offspring if Rebecca IS

NOT carrying a mutation for Tay Sachs.

Probability Genotype Phenotype

4. If Tay-Sachs was sex-linked, describe why it would affect more males than females.

RUBRIC FOR ASSESSMENT 17 GENETICS

1. Identify the autosomal pattern of inheritance in which Tay Sachs is passed from one generation to the next using the evidence in Figure 2. Explain your reasoning.


Students identify that it is a recessive pattern of inheritance because the trait appears in the children but not their parents.


Student identifies that it is a recessive pattern of inheritance but does not give an explanation or gives an incorrect or irrelevant explanation.


Student identifies that it is a dominant pattern of inheritance or does not identify any pattern of inheritance (e.g. “it’s genetic”) with or without an explanation.

2. Identify both Mom and Dad’s genotypes based on the information provided in Figures 1 and 2 and in the family history.


Student indicates that both parents are heterozygous or both parents are carriers. Student may also use an appropriate two-letter genotype for both parents.


Student indicates that one parent is heterozygous (according to the criteria listed for a complete response) but that the other parent has a genotype other than heterozygous.


Student indicates that neither parent is heterozygous (according to the criteria listed for a complete response) or lists the parents’ phenotypes.

5. Years later, Michael (Sarah’s oldest brother) and his new bride, Rebecca, began to plan for a family. Rebecca was tested for the presence of the Tay Sachs mutation because of Michael’s family history.

d. Predict the probability of each genotype and phenotype in the offspring if Rebecca IS carrying a mutation for Tay Sachs.

Mom ________________ Dad ________________


Student indicates

complete genotype of 25% homozygous dominant (ie.TT), 50% heterozygous/carrier for Tay Sachs (Tt) and 25% homozygous recessive (tt)

complete phenotype of 75% healthy and 25% with Tay Sachs

NOTE: Student may use any letter to represent the allele for Tay Sachs and normal genotype. Student may report probability using percentages, ratios, or fractions.


Student meets the genotype criteria or the phenotype criteria but not both.


Student meets neither set of criteria or uses incorrect symbols for alleles (e.g. Nt) or reports incorrect probabilities.

e. Predict the probability of each genotype and phenotype in the offspring if Rebecca IS NOT carrying a mutation for Tay Sachs.


Students’ response must include

complete genotype of 50% homozygous dominant (ie.TT), 50% heterozygous/carrier for Tay Sachs (Tt) and 0 homozygous recessive (tt)

complete phenotype of 100% healthy and 0% with Tay Sachs

NOTE: see note for 5a above


Student meets the genotype criteria or the phenotype criteria but not both.


Student meets neither set of criteria or uses incorrect symbols for alleles (e.g. Nt) or reports incorrect probabilities.

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