Name: ___________________________Period: _______BiologyE Week #32Week of: April 13-17

Day Root Words In-Class Homework

4/13: Monday

Word:Definition:

As in:-

Picture:

- Photo 51

4/14: Tuesday

Word:Definition:

As in:-

Picture:

-DNA Extraction Lab-Grade Graph

4/15: Wednesday

Word:Definition:

As in:-

Picture:-DNA Extraction Quiz-DNA Pre Test-Finish DNA Notes

4/16: Thursday

Word:Definition:

As in:-

Picture:

-DNA Candy Lab-DNA Review

4/17: Friday

Word:Definition:

As in:-

Picture:-DNA Candy Lab Quiz-Week #32 Quiz-Google Classroom

Need Help? Talk to me in class. I’m available during periods 4, 5 and 8. You can call me at 708-434-3616 or email clundgren@oprfhs.org Also, Mr. Hill is in the Tutoring Center before school on Tuesdays and Thursdays. Be sure to use the website

mrlscience.weebly.comDNA Extraction Lab

Introduction:A strawberry is an excellent choice for a DNA extraction. Because each strawberry cell has eight copies of its chromosomes (remember humans have two right before cellular

Name: ___________________________Period: _______division) you will be able to collect a large amount of DNA. Ripe strawberries also contain enzymes that help break down cell walls. In this lab, you will extract the DNA from a strawberry. You must crush the strawberry to break apart its cells, and then add a detergent to dissolve the cell membranes. You will use a filter (cheese cloth) to remove the solids from the mixture. The solution that you collect will contain DNA, proteins, sugars, and other dissolved molecules. You will use ethanol to isolate the DNA from the other dissolved molecules in the solution.

Answer the following questions. What is the purpose of:1. Crushing the strawberry? ______________________________________________

_________________________________________________________________ 2. Adding the detergent? _______________________________________________

________________________________________________________________3. Using the filter (cheese cloth)? _________________________________________

_________________________________________________________________4. Using ethanol? _____________________________________________________

_________________________________________________________________

Purpose: I can extract and observe DNA out of an organism’s cells.

Hypothesis: IF we can extract the DNA from the strawberry’s cells, THEN _________________________________________________________________________________________________________________________________________________________

Materials: (per student partners) 1 larger beaker 1 smaller beaker 1 test tube 1 stirring rod 1 piece cheesecloth 1 strawberry Pinch of salt Drop of soap Ethanol 1 baggie 1 rubber band 1 pipet

Name: ___________________________Period: _______Procedure:

1. Place a strawberry in a plastic baggy.

2. Add one drop/squirt of soap in the bag w/ the pipette in the container.

(please do not play with the soap)

3. Add a pinch of salt into the bag.

4. Pour approximately 20mL of water into the bag (use smaller beaker to

measure –water obtained from any sink).

5. Mash the mixture in the baggy to a pulp (don’t overdo it).

6. Attach the cheesecloth over the top of the beaker with the rubber band.

7. Pour the mixture through the cheesecloth into the larger beaker. (you may

need to use your stirring rod to help it sift through)

8. Transfer the liquid from the large beaker to a test tube.

9. Dispose of the plastic bag and cheesecloth with strawberry pulp in the trash

can.

10.Using a new, clean pipette gently drip COLD ethanol down the side of the test

tube to form a layer on top of the filtered juice (strawberry liquid transferred

from large beaker).

11.Watch for DNA collecting at the interface between the liquids. The DNA is a

cloudy white substance between the ethanol (clear, at the top) and the

strawberry liquid (pink).

12.Using a cleaned stirring rod, gently lift the DNA layer out of the test tube.

13.There ya go! DNA in the nude!!! Examine it under the stereoscope.

14. TEACHER CHECK:______ Analysis: Read to answer the questions below.

DNA (Deoxyribonucleic Acid ) is present in all living things from bacteria to plants to

animals. DNA is the genetic information that is responsible for making all

organisms unique living things. In animals, it is found in almost all cell types: 3

Name: ___________________________Period: _______cheek, muscles, reproductive cells, hair roots, -- anything with a nucleus. DNA is

NOT found in red blood cells because they lack a nucleus. DNA in a cell is about

100,000 times as long as the cell itself. However, DNA only takes up about 10% of

the cell's volume. How can this be? This is because the DNA molecules fold

themselves many times to pack themselves in the cell's nucleus.

1. Where is DNA found in animals? _____________________________________

2. What cells in our bodies do NOT contain DNA & why? ______________________

______________________________________________________________

3. Compare the length of DNA to an average cell. How can DNA fit into a cell?

_____

______________________________________________________________________________

______________________________________________

4. What is the purpose of DNA? _______________________________________

______________________________________________________________

5. What types of organisms have DNA? __________________________________

6. What is a good source of DNA in a person? ______________________________

7. Was your hypothesis supported or not supported? Explain. _________________

______________________________________________________________________________

______________________________________________

DNA Notes Problem: Why is DNA important? Explain the shape of DNA?_________________________________________________________________________________________________________________________________________________________________________________________________________Evidence:What is DNA?

DNA in Prokaryotes vs. Eukaryotes

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Name: ___________________________Period: _______Prokaryotes Eukaryotes

How much

Shape

Where it is found

Types of organisms

What is the basic part/piece/monomer of DNA called?

What are the three parts of a nucleotide?

How many strands make up DNA?

How are the strands held together?

How do the nitrogen bases pair up?

What is the basic shape of DNA called?

Video Clip: http://www.youtube.com/watch?v=u5oCXe6fOFk Discovery of Shape of DNA

Name Contribution to Discovery of ShapeJames Watson and

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Name: ___________________________Period: _______Francis Crick

Erwin Chargaff

Rosalind Franklin

Conclusion: Why is DNA important? Explain the shape of DNA? _________________________________________________________________________________________________________________________________________________________________________________________________________

DNA PracticeComplete the following table.

Name of molecule Sugar, Phosphate, Nitrogen Base

Deoxyribose

Phosphate

Thymine

Guanine

Cytosine

Adenine

DNA stands for:

What is a double helix?

Who are the two men who earned credit for the discovery of the shape of DNA?

Complete the following table.

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Name: ___________________________Period: _______Name of Name of

complementary base

Sugar ---------------------------

Phosphate ---------------------------

Nitrogen base

Nitrogen base

Nitrogen base

Nitrogen base

Label the following picture using the following words:

Deoxyribose Phosphate Adenine Guanine Cytosine Thymine Hydrogen bond Nucleotide (circle and label one)

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Name: ___________________________Period: _______

Role of DNA What is the role of DNA in heredity?You might think that scientists would have been satisfied knowing that genes were made of DNA, but that was not the case at all. Instead, they wondered how DNA, or any molecule for that matter, could do the critical things that genes were known to do. The DNA that makes up genes must be capable of storing, copying, and transmitting the genetic information in a cell. These three functions are analogous (the same) to the way in which you might share a treasured book, as pictured in Figure 12–4.

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Name: ___________________________Period: _______

1. What are the 3 functions of DNA? _______________________________________________________________________________________________________________________________________

Storing Information The first job of DNA, as the molecule of heredity, is to store information. The genes that make a flower purple must somehow carry the information needed to produce purple pigment. Genes for blood type and eye color must have the information needed for their jobs as well, and other genes have to do even more. Genes control patterns of development, which means that the instructions that cause a single cell to develop into an oak tree, a sea urchin, or a dog must somehow be written into the DNA of each of these organisms.

2. Give an example how genes store information. Copying Information Before a cell divides, it must make a complete copy of every one of its genes. To many scientists, the most puzzling aspect of DNA was how it could be copied. The solution to this and other puzzles had to wait until the structure of the DNA molecule became known. Within a few weeks of this discovery, a copying mechanism for the genetic material was put forward.

3. Before scientists could learn how DNA is copied, what had to be known first?

Transmitting Information As Mendel’s work had shown, genes are transmitted from one generation to the next. Therefore, DNA molecules must be carefully sorted and passed along during cell division. Such careful sorting is especially

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Name: ___________________________Period: _______important during the formation of reproductive cells in meiosis. Remember, the chromosomes of eukaryotic cells contain genes made of DNA. The loss of any DNA during meiosis might mean a loss of valuable genetic information from one generation to the next.

4. Careful sorting of DNA is especially important during what phase?

5. The loss of any DNA during meiosis might mean what?

6. Look at Figure 12-3, it represents DNA replication from left to right. What do you notice about the DNA “encyclopedia” after replication is complete? Conclusion: Write three sentences about the three roles of DNA and compare that to a book using the following words: DNA, Storing, Transmitting, Copying, and Book.

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Name: ___________________________Period: _______

Candy DNA Lab Intro: When isolated from a cell and stretched out, DNA looks like a twisted ladder. This shape is called a double helix. The sides of the DNA ladder are called the backbone and the steps of the ladder are pairs of small chemicals called bases. There are four types of chemical bases in DNA: Adenine (A), Cytosine (C), Guanine (G), and Thymine (T). They form pairs in very specific ways: A always pairs with T and C always pairs with G. We say that A & T are complimentary pairs while C & G are complimentary pairs. In this lab will construct a model of DNA using twizzlers as the backbone, marshmallows as the bases, and toothpicks as the bonds that hold it all together.

Purpose: I can construct a model of DNA applying the base pairing rules (A=T, G=C).

Materials: Twizzlers, marshmallows, toothpicks

Method:1 – Use the twizzlers as the backbone of DNA and the marshmallows as the bases of DNA.2 – Stick a marshmallow (base) onto the end of a toothpick and then into the twizzlers (backbone). (see Figure 1)3 – Using the base pairing rules, color code the bases and stick their complimentary pair onto the other side of the toothpick. (see Figure 2)The base pairing rules are color coded as shown in Table 1.

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Figure 1

Table 1 Figure 2

Name: ___________________________Period: _______

Complete the diagram below by writing your created DNA sequence and its compliment.

4 – Attach the second twizzler (backbone). (see Figure 2)5 –Twist the DNA molecule so that it looks like a double helix. (see Figure 3)6 – To receive full credit you must verify with your teacher your model is correct. Then you can eat it!

Analysis Questions: (to answer, use this lab, notes and/or textbook) WRITE IN COMPLETE SENTENCES!!!!!!!!!!!

1.TEACHER CHECK: ____________________2. In your model, what represents the backbone of DNA?

3. What is the purpose of the backbone?

4. In your model, what represents the different bases of DNA?

5. What are the base pairing rules?

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Figure 3

Name: ___________________________Period: _______6. How did you illustrate the base pairing rules in this model?

7. What was the purpose of step 5? That is, why were you twisting the model?

8. In your model, what are the toothpicks representing?

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Name: ___________________________Period: _______DNA Reading #1

Its one thing to say that the molecule called DNA carries genetic information, but it would be quite another thing to explain how it could do this. DNA must not only specify how to assemble proteins, but how genes can be replicated and inherited. DNA has to be a very special molecule, and it's got to have a very special structure. As we will see, understanding the structure of DNA has been the key to understanding how genes work.

1. What does DNA “carry”? _________________________________________

Deoxyribonucleic acid, or DNA, is a unique molecule indeed. DNA is a nucleic acid macromolecule made up of nucleotides joined into long strands or chains by covalent bonds.

2. What does “DNA” stand for? ______________________________________

As you may recall, nucleic acids are long, slightly acidic molecules originally identified in cell nuclei. Like many other macromolecules, nucleic acids are made up of smaller subunits, linked together to form long chains. Nucleotides are the building blocks of DNA nucleic acids. The figure shows the nucleotides in DNA. These nucleotides are made up of three basic components: a sugar called deoxyribose, a phosphate group, and a base.

3. What are the building blocks of DNA? ______________________________4. What are the parts of a nucleotide? ________________________________

____________________________________________________________

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Name: ___________________________Period: _______DNA has four kinds of bases: adenine (AD uh neen), guanine (GWAH neen), cytosine (SY tuh zeen), and thymine (THY meen). Biologists often refer to the nucleotides in DNA by the first letters of their base names: A, G, C, and T. The nucleotides in a strand of DNA are joined by covalent bonds formed between the sugar of one nucleotide and the phosphate group of the next. The bases stick out sideways from the nucleotide chain. The nucleotides can be joined together in any order, meaning that any sequence of bases is possible.

5. List the bases contained in DNA. ___________________________________

6. What type of bond joins the bases with the sugar and phosphate? _______ ___________________________________________________________

7. Do the bases have to be in a specific order? __________________________

The four different nucleotides, like the 26 letters of the alphabet, could be strung together in many different sequences, so it was possible they could carry coded genetic information. However, so could many other molecules, at least

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Name: ___________________________Period: _______in principle. Biologists wondered if there was something more to the structure of DNA.DNA is made up of nucleotides, each with a deoxyribose sugar molecule, a phosphate group, and a base. The four bases are adenine (A), guanine (G), cytosine (C), and thymine (T).

8. List the parts of a DNA nucleotide. _______________ _______________________________________________

9. Sketch a nucleotide molecule.

DNA Reading #2Solving the Structure of DNAKnowing that DNA is made from long chains of nucleotides was only the beginning of understanding the structure of this molecule. The next step required an understanding of the way in which those chains are arranged in three dimensions.

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Name: ___________________________Period: _______One of the puzzling facts about DNA was a curious relationship between its nucleotides. Years earlier, Erwin Chargaff, an Austrian-American biochemist, had discovered that the percentages of adenine [A] and thymine [T] bases are almost equal in any sample of DNA. The same thing is true for the other two nucleotides, guanine [G] and cytosine [C]. The observation that [A] = [T] and [G] = [C] became known as “Chargaff's rule.”

1. Describe Chargaff’s rule. _____________________________________________________________________________________________________

In the early 1950s, the British scientist Rosalind Franklin began to study DNA. Franklin used a technique called X-ray diffraction to get information about the structure of the DNA molecule. First, she purified a large amount of DNA, then stretched the DNA fibers in a thin glass tube so that most of the strands were parallel. Next, she aimed a powerful X-ray beam at the concentrated DNA samples and recorded the scattering pattern of the X-rays on film. Franklin worked hard to obtain better and better patterns from DNA until the patterns became clear. The result of her work is the X-ray photograph shown to the right, taken in the summer of 1952.

2. What was Rosalind Franklin’s contribution to the discovery of the DNA molecule? ____________________________________________________________________________________________________________________________________________________________________________

While Franklin was continuing her research, James Watson, an American biologist, and Francis Crick, a British physicist, were also trying to understand the structure of DNA. They built three-dimensional models of the molecule that were made of cardboard and wire. They twisted and stretched the models in various ways, but their best efforts did nothing to explain DNA's properties. Then, early in 1953, Watson was shown a copy of Franklin's remarkable X-ray

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Name: ___________________________Period: _______pattern. The effect was immediate. In his book The Double Helix, Watson wrote: “The instant I saw the picture my mouth fell open and my pulse began to race.” The clues in Franklin's X-ray pattern enabled Watson and Crick to build a model that explained the specific structure and properties of DNA. The pair published their results in a historic one-page paper in April of 1953, when Franklin's paper describing her X-ray work was also published. Watson and Crick's breakthrough model of DNA was a double helix, in which two strands of nucleotide sequences were wound around each other.

3. What was James Watson and Francis Crick’s contribution to the discovery of the DNA molecule? _______________________________________________________________________________________________________

Watson and Crick 1953 Crick’s Original Sketch Modern Computer Model

The Double-Helix ModelA double helix looks like a twisted ladder. In the double-helix model of DNA, the two strands twist around each other like spiral staircases. Watson and Crick realized that the double helix accounted for Franklin's X-ray pattern. Further still, it explained many of the most important properties of DNA. The double-helix model explains Chargaff's rule of base pairing and how the two strands of DNA are held together. This model can even tell us how DNA can function as a carrier of genetic information.

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Name: ___________________________Period: _______4. Describe “double helix”. _________________________________________

___________________________________________________________

Antiparallel Strands One of the surprising aspects of the double-helix model is that the two strands of DNA run in opposite directions. In the language of biochemistry, these strands are “antiparallel.” This arrangement enables the bases on both strands to come into contact at the center of the molecule. It also allows each strand of the double helix to carry a sequence of nucleotides, arranged almost like letters in a four-letter alphabet.

5. What is antiparallel? ________________________________________________________________________________________________________

Hydrogen Bonding At first, Watson and Crick could not explain what forces held the two strands of DNA's double helix together. They then discovered that hydrogen bonds could form between certain bases, providing just enough force to hold the two strands together. As you may recall, hydrogen bonds are relatively weak chemical forces.Watson and Crick's model showed that hydrogen bonds could create a nearly perfect fit between bases along the center of the molecule. However, these bonds would form only between certain base pairs—adenine with thymine, and guanine with cytosine. This nearly perfect fit between A–T and G–C nucleotides is known as base pairing.

6. What is the purpose of hydrogen bonds in DNA? ______________________ ___________________________________________________________

7. What is base pairing? ___________________________________________ ___________________________________________________________

Once they observed this process, Watson and Crick realized that base pairing explained Chargaff's rule. It gave a reason why [A] = [T] and [G] = [C]. For every

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Name: ___________________________Period: _______adenine in a double-stranded DNA molecule, there has to be exactly one thymine. For each cytosine, there is one guanine. The ability of their model to explain Chargaff's observations increased Watson and Crick's confidence that they had come to the right conclusion, with the help of Rosalind Franklin.

8. Complete the following base pairs:a. A = _______b. T = _______c. C = _______d. G = _______

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