Biology Review
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Transcript of Biology Review
MCAS Review2012
Chemistry of Life
Define Organic
Compounds that contain carbon atoms that are covalently bonded to other elements, typically hydrogen, oxygen, and other carbon atoms
C-H-O
All living things are made up of 6 essential elements: SPONCH
Name the 6 elements of life:
Sulfur
Phosphorus
Oxygen
Nitrogen
Carbon
Hydrogen
Elements join together by chemical bonds to form compounds. Name the 3 types of chemical bonds
Covalent Bonds
Ionic Bonds
Hydrogen Bonds
There are 4 major categories of organic molecules that are made up of the SPONCH elements.
Lipids
Carbohydrates
Proteins
Nucleic Acids
Lipids
Elements:
Structure:
Function:
Examples:
Carbon, Hydrogen, Oxygen
3 fatty acid chains linked by a glycerol backbone
Building blocks of the cell membrane, energy storing molecules
Steroids like cholesterol & fats
Carbohydrates
Elements:
Structure:
Function:
Examples:
Carbon, Hydrogen, Oxygen
Monosaccharides bonded together in long chains (poly)
Key source of energy!
Sugar and starch
Proteins
Elements:
Structure:
Function:
Examples:
Carbon, Hydrogen, Oxygen, & Nitrogen
Amino acids bonded in long chains that coil around each other into specific shapes
Enzymes (speed up reactions), structural (hair, muscle, skin, etc), antibodies (protect body)
Enzymes, collagen, antibodies
Nucleic Acids
Elements:
Structure:
Function:
Examples:
Carbon, Hydrogen, Oxygen, Nitrogen & Phosphorus
Long chain of nucleotides bonded together
DNA (store genetic info), and RNA (aid in building proteins)
DNA, RNA
Define Chemical Reaction:
The process during which chemical bonds between atoms are broken and new ones are formed, producing one or more different substances
AB + CD AC +BD
Write an example of a chemical reaction and label the reactants and products:
NaCl Na+ + Cl-
Reactant Products
Define Activation Energy
The energy needed to start a chemical reaction
Define Enzyme:
Proteins that increase the speed of a chemical reaction
Any factors that affect the shape of an enzyme affect the enzyme’s activity.
What effect does pH and temperature have on an enzyme’s function?
pH and temp must be within an optimal range for an enzyme to do its job
If pH and/or temp are not in the proper range then the enzyme may change shape or become inactive
Cell Biology
Draw a Plant Cell
Draw an Animal Cell
Complete the Table:
Cell Part Function (job) Plant/Animal/Both
Plasma Membrane
Encloses the cell & separates the cytoplasm from its surroundings, regulates what enters & leaves the cell
Both
Nuclear Envelope
Separates the nucleus from the cytoplasm
Both
Nucleus Stores DNA and makes mRNA Both
Nucleolus Located inside the nucleus, mRNA is made here
Both
Complete the Table:
Cell Part Function (job) Plant/Animal/Both
Cytoplasm Interior part of the cell made up of fluid that cushions all organelles
Both
Mitochondria Provide energy to the cell Both
Endoplasmic reticulum
Process & modify proteins that were made in the nucleolus
Both
Golgi apparatus
Package proteins into vesicles for export throughout the cell
Both
Complete the Table:
Cell Part Function (job) Plant/Animal/Both
Lysosome Contain digestive enzymes to clean up the cell
Both
Ribosome Aid in protein synthesis Both
Vacuole Help digestion of materials, store nutrients & keep cell pressure
Plant
Cell Wall Support & maintain shape, protect cell from damage, connect to nearby cells
Plant
Complete the Table:
Cell Part Function (job) Plant/Animal/Both
Chloroplast Use light energy to make food (carbohydrates) through photosynthesis
Plant
Cytoskeleton Help to maintain cell shape & aids in movement of materials in the cell
Both
Centriole Help the formation of the spindle to move chromosomes during mitosis
Animal
Prokaryote vs. Eukaryote
Prokaryote
No nucleus
No organelles
Reproduce asexually
Small
Example: bacteria
Eukaryote
True nucleus
Organelles
Reproduce either sexually or asexually
Larger
Example: plant, animal, protist, fungi cells
Draw the structure of the cell membrane:
Image source: library.thinkquest.org
What is it called?
Phospholipid bilayer
Diffusion, Osmosis, & Facilitated Diffusion
Diffusion –
Osmosis –
Facilitated Diffusion -
Passive transport across a membrane from an area of high concentration to low concentration (downstream)**Does not require energy
Diffusion of Water**Does not require energy
Passive transport across a membrane from an area of high concentration to low concentration that requires carrier proteins**Does not require energy
What are the 6 Kingdoms of Life?
Eubacteria
Archaebacteria
Protista
Fungi
Plants
Animals
Identify the formulas:
6H20 + 6CO2 -> C6H12O6 + 6O2
C6H12O6 + 6O2 -> 6H20 + 6CO2 + energy
Photosynthesis
Cellular Respiration
Define Photosynthesis
The process that captures the sunlight’s energy in the chloroplast of plant cells and converts it to glucose (sugar), the food for life
Define Cellular Respiration
The process that breaks down glucose to make energy for the cells to use
How are Photosynthesis & Cellular Respiration related?
They are opposites!
One makes sugar (photosynthesis)
One breaks sugar (respiration)
Humans need oxygen to be able to perform cellular respiration and gain ATP energy.
What would happen to the oxygen levels on Earth if photosynthesis stopped?
Oxygen
What happens when a phosphate group is removed from ATP?
Energy is released for the cell to use!
Compare the energy levels of ATP, ADP, and AMP to the energy levels of a battery
ATP (Adenosine Triphosphate) is like a fully charged battery with 3 phosphates
ADP (Adenosine Diphosphate) is like a partially charged battery with 2 phosphates
AMP (Adenosine Monophosphate) is like a dead battery with only 1 phosphate
Draw and label the phases of the cell cycle:
What is the function of the cell cycle?
To successfully make new cells for growth of the organisms or replacement of dead or damaged cells
Compare and contrast mitosis and meiosis
Describe fertilization using haploid, gamete, diploid, and zygote
Genetics
What is DNA?
Deoxyribonucleic acid
The material that stores the information that determines an organism’s characteristics (traits)
Draw and Label a Nucleotide
How do nucleotides form the structure of DNA? Nucleotides link
together to form a chain
Corresponding nucleotides match-up according to the base-pairing rules to form the second chain
Draw a molecule of DNA
Sugar/Phosphate backbone
Nucleotide
Nitrogen bases
Hydrogen bonds
What is a double helix?
2 strands of nucleotides attached by hydrogen bonds in the middle and twisted together
Base-pairing Rules:
Adenine – Thymine
Guanine - Cytosine
What is the relationship between Gene and DNA?
Genes are sections of DNA that code for proteins
The rest of the DNA codes for nothing!
3 Steps of DNA Replication:
1. DNA helicase unwinds the double helix by breaking the hydrogen bonds, forming the replication fork
2. DNA polymerase adds complementary nucleotides to the separated DNA strands
3. DNA polymerase continues until it reaches the end of the molecule, forming 2 identical DNA molecules
Gene expression is the process of turning the genes in the DNA into a phenotype that can be seen
Draw and label the 2 phases of gene expression, and where they happen in the cell
End Products
Replication Transcription Translation
Start DNA DNA RNA
End DNA RNA Protein
Types of DNA Mutations:
What will happen if there is a mutation in a gamete?
Gametes are egg and sperm cells
A mutation would result in a genetic disorder or failure to fertilize (no zygote)
Two parents are heterozygous for brown eyes Bb x Bb
B b
B BB Bb
b Bb bb
Genotype Ratio:1BB:2Bb:1bb
Phenotype Ratio:3 Brown:1 Blue
What Percent of the Offspring have Blue Eyes?
25%
Why do men experience male-pattern baldness more than women?
The trait is sex-linked
Men only have one X chromosome, so whatever allele they get for hair, whether it is the dominant normal or the recessive allele that causes baldness, it will show.
Men have XY and women have XX
Using Mendel’s laws of segregation and independent assortment, explain why not all tall people have brown hair. The law of segregation says that during
meiosis the alleles separate independently during Metaphase II of meiosis
The law of independent assortment says that homologous chromosomes separate independently during Metaphase I of meiosis
The two traits are chosen randomly
Describe an example for each of the following:Codominance – Polygenic traits -
Incomplete dominance – Multiple alleles -
Both forms of the trait are displayed – dalmation dog with black spots
Several genes control one trait – skin color or hair color
Neither allele for the trait is dominant – white flower X red flower = pink!
More than 2 alleles for one trait – Blood types A, B, AB, O
Anatomy & Physiology
Describe the 4 levels of structural organization in the human body
Cells
Tissues
Organs
Organ Systems
Digestive System
Function Path of Food (all major organs)
Important Digestive Enzymes
Breaks down and absorbs nutrients from food; removes waste; maintains water balance
Mouth – pharynx – epiglottis – Esophagus – stomach – small intestine – large intestine – rectum – anus
Amylase – in saliva, breaks down sugar
Pepsin – in stomach, breaks down protein
Lipase – in pancreas, breaks down fat
Circulatory System
Function Path of Blood (all major organs)
Transports nutrients, wastes, hormones, and gases
Capillary drops off nutrients to cell & picks up waste – venule – vein – right atrium – right ventricle – pulmonary artery – capillaries (lungs) – pulmonary vein – left atrium – right atrium – aorta – artery – arteriole - capillary
Excretory System
Function of Kidneys Function of Liver
Regulate the amount of water and salts in the blood
Secretes bile which helps break down fats and absorb vitamins; regulates sugar levels in blood
Respiratory System
Function Path of oxygen/carbon dioxide (all major organs)
Move air into and out of lungs; controls gas exchange between blood and lungs
Mouth/nose – pharynx – epiglottis – larynx – trachea – bronchi – bronchioles – alveoli – bronchioles – bronchi – trachea – larynx – epiglottis – pharynx – mouth/nose
Nervous System
Function Basic Unit – The Neuron (How it Works)
Major Components
Regulates behavior; maintains homeostasis; regulates other organ systems; controls sensory and motor functions
Neuron is made up of dendrites that receive an electrical signal which is then carried to the cell body which is then carried through the axon and is then passed on to the next neurons dendrites
Peripheral NS – sensory & motor neurons
Central NS – brain & spinal chord
Muscular/Skeletal System
Function of Muscles 2 functions of bones
Help in movement of bones; contraction of heart and other organs
Provide shape and support to the bodyProduce blood cells and platelets in the marrow of the bone
3 types of muscle tissue
Skeletal – muscles that move bones
Smooth – involuntarily controlled; the muscles that cause the stomach to contract
Cardiac – involuntarily controlled; is the muscle that makes up the heart
2 Types of Connective Tissue
Ligament – attaches bone to bone
Tendon – attaches muscle to bone
Define homeostasis
The process of maintaining internal stability within an organism
Explain how body temp is maintained When it is cold out, the sensory neurons (nervous
system) send a signal to the spinal cord then the brain
The brain interprets the signal and sends a message to the motor neurons
The motor neurons trigger the muscles in your body to contract/relax over and over, which causes the bones to move
This increases warmth in the body
The heart also beats faster sending warm blood more quickly throughout the body to increase warmth
Evolution & Biodiversity
What is Evolution by Natural Selection? Evolution is the change of a species over time
This happens due to some kind of change in the environment of an organism. It must adapt or die
If there is a mutation or trait that is advantageous, it will be selected for (natural selection)
Organisms with the advantageous trait are picked as mates and reproduce more successfully, passing on the good genes
Over time, the build-up of differences is called evolution
Example:
Evidence for Evolution
Fossil Record
Comparative Anatomy Genetic & molecular similarities
Homologous Structures
Vestigial Structures
Bones from Lucy show a relationship between apes and humans
The forearm of penguin, human, lizard, and bats all have the same bones
Whale used to be a 4-legged animal on land and then moved into the sea and evolved so that the pelvis and legs have lost their function
Gorilla and human have an almost identical hemoglobin protein in the blood
Speciation
Mutation – elephant with NO tusks
Reproductive Isolation – does not get hunted by poachers and lives freely
Natural Selection – live longer since they are not hunted and are selected by other elephants
Divergence – over time if populations stay separated they may continually adapt and develop more and more genetic differences
New Species – if the 2 populations become so genetically different that they no longer breed successfully, they are considered 2 species
Define Species:
The basic classification of living things
What characteristics are organisms classified (or grouped) by?
Form and structure
Behavior
Molecular similarities
8 Levels of Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Binomial Nomenclature Rules:
The first word is the Genus name and is capitalized
The second word is the species and is lowercase
Humans = Homo sapiens
Define Biodiversity
The variety of organisms, their genetic differences, and the communities and ecosystems in which they occur
How does evolution affect biodiversity?
Evolution by natural selection offers a means by which organisms can become more and more different over time to a point where they become new species.
Every living thing experiences evolution at some speed
The large biodiversity of life on Earth can be attributed to the process of evolution
Ecology
What is Ecology?
The study of interaction of living organisms with one another and with their physical environment
What are the components of an ecosystem?
Biotic factors (living) – plants, animals, bacteria, fungi
Abiotic factors (non-living) – soil, water, weather, climate
Define Community
All the living things in one ecosystem
Flow of energy
Energy begins with the producers who take the sun’s energy and turn it into food
Primary consumers (herbivores) obtain their energy by eating the producers
Energy moves to the secondary consumers (omnivores/carnivores) who obtain their energy by eating the herbivores
Lastly, when all organisms die, decomposers obtain their energy and recycle it back into the ecosystem
What does a food chain show?
The path of energy flow in a specific ecosystem
Grass -> Rabbit -> Fox -> Wolf
How do food chains relate to food webs?
A food web is made up of many interconnected food chains
Why are energy pyramids usually no more than 4 trophic levels?
As you go up the trophic levels in an energy pyramid, energy is lost as heat from the organisms that are not eaten (die)
Once you reach the top there is very little energy available
DecomposersDecomposers belong anywhere outside the pyramid. This is because of their niche. Decomposers niche in an ecosystem is to obtain energy from any dead organism and then to recycle the nutrients back into the ecosystem
Water Cycle
Water starts in the nonliving as vapor in the atmosphere (clouds) then falls as rain, goes into soil, is taken up by the roots of plants (now part of the living) and then transpired back into the atmosphere
Carbon Cycle
Carbon in form of carbon dioxide
(CO2)
PhotosynthesisCellular Respiration
Carbon in form of food and living
things
Nitrogen Cycle
Nitrogen in the non-usable form of
nitrogen gas
Nitrogen-fixing bacteria
Denitrifying bacteria
Nitrogen in the usable form of nitrates and
ammonia
Biological Communities
CommensalismInteraction between 2 organisms where 1 benefits and the other is neither helped nor harmed
CompetitionWhen 2 organisms use the same resources and there is a struggle to obtain the resources
ParasitismInteraction between 2 organisms where 1 benefits and the other is harmed
MutualismInteraction between 2 organisms where both benefit
Predator/PreyInteraction between 2 organisms where the predator needs to hunt and kill the prey for food/energy in order to survive
Define Population
A group of organisms of the same species living in one area
Factors that affect population size and biodiversity:
Climate change
Loss of resources
Changes in symbiotic relationships
Pollution due to human activity
Good Luck on the MCAS Biology Exam!You can do it!