keystone review

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Basic Biological Principles
Module A Anchor 1
Key Concepts:
- Living things are made of units called cells, are based on a universal genetic code, obtain and use
materials and energy, grow and develop, reproduce, respond to their environment, maintain a stable
internal environment, and change over time.
-
Prokaryotic cells do not separate their genetic material within a nucleus. In eukaryotic cells, the
nucleus separates the genetic material from the rest of the cell.
-
The cells of multicellular organisms become specialized for particular tasks and
communicate with one another.
Vocabulary:
Homeostasis
Eukaryote
Cell membrane
Cell
Evolution
Nucleus
DNA
Prokaryote
Asexual reproduction
Sexual reproduction
Membrane-bound organelles
Cell specialization
Characteristics of Life:
1. List the characteristics of life common to all living things.
2. If an organism lacks any of these characteristics, is it considered living? Why or why not?
3. Which of the following characteristics of living things explains why birds fly south for the winter?
A. Living things respond to their environment
B. Living things maintain homeostasis
C. Living things are made of cells
D. Living things are based on a universal genetic code
4. Which characteristic(s) of living things is more important to the survival of the species as a whole,
rather than the individual organism? Why?
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Prokaryotes vs. Eukaryotes:
1. Compare and contrast prokaryotes and eukaryotes in terms of structures; list specific organelles which
are present in each, as well as other structural similarities and differences.
2. Compare and contrast prokaryotes and eukaryotes in terms of genetic material.
3. How are the similarities and differences between prokaryotic and eukaryotic cells dependent on their size?
4. How do the structures of prokaryotic and eukaryotic cells influence their functions?
5. Not all cells are alike. Which of the following is NOT a true statement about differences between
cells?
A. Cells come in many different shapes
B. Different kinds of cells are different sizes
C. Some cells have a nucleus and others do not
D. Most cells have a membrane, but some do not
Levels of Organization:
1. Describe the relationship between organelles, cells, tissues, organs, and organ systems.
2. Cells in multicellular organisms have many sizes and shapes. These differences are referred to as cell
specialization. Cell specialization allows cells to:
A. Reproduce
B. Perform different functions
C. Respond to their environment
D. Be less complex
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3. The cells of unicellular organisms are:
A. Specialized to perform different tasks
B. Larger than those of multicellular organisms
C. Able to perform all the functions necessary for life
D. Unable to respond to changes in their environment
4. Give an example of changes that take place as cells in a multicellular organism differentiate.
5. Explain the relationship between cell specialization, multicellular organisms, and homeostasis.
6. How are unicellular and multicellular organisms alike? How are they different?
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Biological Principles- ANSWER KEY
Module A Anchor 1
Characteristics of Life:
1. List the characteristics of life common to all living things.
Living things are made of cells, are based on a universal genetic code, obtain and use materials and energy,
grow and develop, reproduce, respond to their environment, maintain a stable internal environment, and
change over time.
2. If an organism lacks any of these characteristics, is it considered living? Why or why not? No –
nonliving things can contain some of the characteristics of life. For example, a chemical can react to the
environment.
3. Which of the following characteristics of living things explains why birds fly south for the
winter?
A. Living things respond to their environment
4. Which characteristic(s) of living things is more important to the survival of the species as a
whole, rather than the individual organism? Why?
Reproduction – ensures the continuation of the species, but has no direct benefit to the organism Change
over time – refers to evolution, which occurs to species and not to individual organisms. Individual
organisms survive or do not survive, altering the species as a whole and allowing it to continue existing.
Prokaryotes vs. Eukaryotes:
1. Compare and contrast prokaryotes and eukaryotes in terms of structures; list specific
organelles which are present in each, as well as other structural similarities and differences.
o Prokaryotes – No nucleus, no membrane-bound organelles, unicellular
o Eukaryotes – contain genetic material within nucleus, contain membrane-bound organelles,
can be unicellular or multicellular
o Both – contain cell-membrane, cell wall, ribosomes, contain genetic material
2. Compare and contrast prokaryotes and eukaryotes in terms of genetic material. Prokaryotes do
not contain their genetic material within a nucleus. Contain circular pieces of DNA concentrated within a
nucleoid. Some contain plasmids, which can be shared with other prokaryotes.
Eukaryotes contain their genetic material in chromosomes within a nucleus.
3. How are the similarities and differences between prokaryotic and eukaryotic cells dependent on
their size?
Prokaryotic cells are smaller; therefore have a more favorable surface-area to volume ratio. This makes
transport of materials into and out of the cell much easier. Prokaryotes are therefore able to lack
membrane-bound organelles and have less complex internal structure. Eukaryotes are generally larger than
prokaryotes, and have a less favorable surface-area to volume ratio. This makes transport more
complicated, requiring them to contain a larger variety of organelles.
4. How do the structures of prokaryotic and eukaryotic cells influence their functions? Prokaryotes
contain everything necessary to carry out life processes; however, they do lack the complex internal
structure of eukaryotes. The more complex internal structure of eukaryotes allows them to perform a
larger array of functions, including those requiring multicellularity.
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5. Not all cells are alike. Which of the following is NOT a true statement about differences
between cells?
D. Most cells have a membrane, but some do not
Levels of Organization:
1. Describe the relationship between organelles, cells, tissues, organs, and organ systems. Groups of a
variety of organelles make up cells. Groups of the same cell type make up tissues. Groups of multiple
tissues make up organs. Groups of organs with the same overall purpose working together make up organ
systems.
2. Cells in multicellular organisms have many sizes and shapes. These differences are referred to as
cell specialization. Cell specialization allows cells to:
B. Perform different functions
3. The cells of unicellular organisms are:
C. Able to perform all the functions necessary for life
4. Give an example of changes that take place as cells in a multicellular organism differentiate.
Organisms originally begin as undifferentiated stem cells. These stem cells are capable of differentiating into
any cell type. A number of factors influence the type of cell into which a stem cell differentiates. These
factors are not all fully understood. Once a cell reaches its final differentiated state, it can no longer
naturally change.
5. Explain the relationship between cell specialization, multicellular organisms, and
homeostasis.
Multicellular organisms are large and complex; therefore, they require more complicated systems in order to
maintain homeostasis. Multicellular organisms accomplish this by designating particular functions to
particular cells. This allows different cells to work together to maintain homeostasis within a larger
organism.
6. How are unicellular and multicellular organisms alike? How are they different?
Alike – both are able to perform all of the functions necessary for life. Both can perform a large array of
functions.
Different – the cell of a unicellular organism is capable of performing all its necessary functions. A
multicellular organism, due to its large size and complex structure, differentiates different cells for different
functions.
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Chemical Basis of Life
Module A Anchor 2
Key Concepts:
- Water is a polar molecule. Therefore, it is able to form multiple hydrogen bonds, which account for
many of its special properties.
- Water’s polarity gives it the ability to dissolve both ionic compounds and other polar molecules.
- Carbon can bond with many elements, including hydrogen, oxygen, phosphorus, sulfur, and
nitrogen to form the molecules of life.
- The function of macromolecules is directly related to their chemical structure.
- Living things use carbohydrates as their main source of energy. Plants, some animals, and other
organisms also use carbohydrates for structural purposes.
- Lipids can be used to store energy. Some lipids are important parts of biological membranes
and waterproof coverings.
- Nucleic acids store and transmit hereditary, or genetic, information.
- Some proteins control the rate of reactions and regulate cell processes. Some proteins build tissues
such as bone and muscle. Others transport materials or help fight disease.
- Chemical reactions always involve changes in the chemical bonds that join atoms in
compounds.
- Chemical reactions that release energy often occur spontaneously. Chemical reactions that absorb
energy will not occur without a source of energy.
- Enzymes speed up chemical reactions that take place in cells. This function is directly related to
their structure, with each enzyme being specifically shaped to catalyze one particular reaction.
Loss of structure causes loss of function.
- Temperature, pH, and regulatory molecules can affect the activity of enzymes.
Vocabulary:
Hydrogen bond
Adhesion
Heat of vaporization
Carbohydrate
Triglyceride
Fatty acid
Secondary structure
Enzyme
Substrate
solution
polarity
polymer
monosaccharide
phospholipid
protein
tertiary structure
catalyst
product
pH scale
freezing point
nucleic acid
polysaccharide
steroid
amino acid
quaternary structure
activation energy
reactant
cohesion
monomer
nucleotide
lipid
wax
primary structure
chemical reaction
active site
Properties of Water:
1. Describe the following properties of water and explain how each is important to living things: cohesion,
adhesion, polarity, heat of vaporization, freezing point.
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2. How is polarity related to cohesion and adhesion?
3. Compared to most other substances, a great deal of heat is needed to raise the temperature of water by a
given amount. This is because water
A. is an acid
B. readily forms solutions
C. has a high heat capacity
D. acts as a buffer
4. Frozen water is less dense than liquid water. Explain why this is important for aquatic organisms.
Macromolecules:
1. How is the structure of carbon related to its function in macromolecules? Think about the types of
shapes carbon can form and why.
2. Describe the processes of hydrolysis and dehydration synthesis. How are they related to each other?
3. List and draw the monomer and polymer units of each macromolecule along with their function in
living things: carbohydrates, proteins, nucleic acids.
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4. List and draw the types of lipids, along with the subunits and uses of each.
5. Why are carbohydrates, proteins, and nucleic acids considered polymers, while lipids are not?
6. How is the structure of each of the four macromolecules related to its function in living things?
 Carbohydrate –

Nucleic acid –

Protein –

Lipid -
7. How does the structure of a protein make it capable of such a large range of function?
Enzymes:
1. What occurs during a chemical reaction?
2. What is the difference between a product and a reactant?
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3. Energy is used differently in different types of chemical reactions. Explain how energy use differs in
energy-releasing and energy-absorbing reactions. Which type often requires a catalyst?
4. How is energy related to the products and reactants of a chemical reaction?
5. What is the role of an enzyme in living organisms?
6. In what way do enzymes increase the rate of reactions? How do enzymes accomplish this task?
7. Describe the cycle in which enzymes and substrate interact.
8. How/Why is the structure of an enzyme so important to its function in living things? Why does the
structure of an enzyme determine the type of reaction it will catalyze?
9. What happens to enzyme function when the temperature or pH conditions change? Why?
10.The energy needed to get a reaction started is the:
A. adhesion energy
C. cohesion energy
B. activation energy
D. chemical energy
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Chemical Basis of LifeANSWER KEY
Properties of Water:
Module A Anchor 2
1. Describe the following properties of water and explain how each is important to living things:
cohesion, adhesion, polarity, heat of vaporization, freezing point.
Cohesion – attraction between molecules of the same substance, water bonds to water Adhesion –
attraction between molecules of different substances, water bonds to another
Molecule
Cohesion and adhesion help life in a variety of ways: they aid in the transport of liquids in plants, provide
surface tension for aquatic organisms, etc.
Polarity – Polar molecules have ends with opposite charges. The oxygen atom of a water molecule more
strongly attracts the electrons involved in the covalent bonds between oxygen and hydrogen. This
gives the oxygen a slight negative charge and the hydrogen a slight positive charge. The polar nature
of water makes it the universal solvent.
Heat of vaporization – it takes a large amount of energy to change the state of water. This benefits aquatic
organisms, as bodies of water maintain fairly stable temperature conditions.
2. How is polarity related to cohesion and adhesion?
The attraction between molecules that causes cohesion and adhesion is the result of polarity. Polarity creates
molecules with charged ends. Opposite charges attract, causing cohesion and adhesion.
3. Compared to most other substances, a great deal of heat is needed to raise the temperature of
water by a given amount. This is because water
C. has a high heat capacity
4. Frozen water is less dense than liquid water. Explain why this is important for aquatic
organisms.
Frozen water floats, create a buffer for aquatic organisms in winter. This buffer prevents the entire body of
water from freezing and killing the organisms within it.
Macromolecules:
1. How is the structure of carbon related to its function in macromolecules? Think about the types
of shapes carbon can form and why.
Carbon atoms have four valance electrons. This allows them to form strong covalent bonds with a number of
elements. Carbon can also bond with itself, allowing it to form long chains or rings of carbon atoms.
2. Describe the processes of hydrolysis and dehydration synthesis. How are they related to each other?

They are opposite processes.
o Hydrolysis – molecules are broken into smaller pieces. Water is added.
o Dehydration synthesis – oxygen and hydrogen are removed from two molecules, opening up
bonding sites where they can join. The oxygen and hydrogen are joined to form water.
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3. List and draw the monomer and polymer units of each macromolecule along with their
function in living things: carbohydrates, proteins, nucleic acids.
Carbohydrate – monomer: monosaccharide
energy and structure
Protein– monomer: amino acid
highly varied
polymer: polysaccharide function:
polymer: polypeptide function –
Nucleic acid – monomer: nucleotide
store and transmit hereditary information
polymer: nucleic acid function:
4. List and draw the types of lipids, along with the subunits and uses of each.
Phospholipid – consists of fatty acid, phosphate group, glycerol, used in cell membranes Wax –
subunits are alcohol and fatty acids, used in structure and water-proofing Steroid – carbon-ring
structure, used as chemical messenger
Triglyceride – subunits are glycerol and three fatty acids, used for energy storage
5. Why are carbohydrates, proteins, and nucleic acids considered polymers, while lipids are not?
Carbohydrates, proteins, and nucleic acids are all composed of one repeating subunit. Lipids have a variety
of subunits, and are grouped only by their shared nonpolar nature.
6. How is the structure of each of the four macromolecules related to its function in living
things?
 Carbohydrate – Energy is stored in bonds. Carbohydrates contain large numbers of bonds.

Nucleic acid – Nucleic acids are well-suited to store information in the repeating sequences of their
base pairs. They are also structured to split and replicate easily, allowing the genetic information to
be easily passed on to offspring.

Protein – Proteins have 20 different amino acids, which can be arranged in any order. Proteins also
have four levels of structure: primary, secondary, tertiary, and quaternary. An alteration in any of
these levels alters the function of the protein. This allows for a large variety of function.

Lipid – Lipids are nonpolar, allowing them to function in cell membranes and waterproofing.
Triglycerides contain large numbers of bonds, making them ideal for energy storage.
7. How does the structure of a protein make it capable of such a large range of function?
Proteins have 20 different amino acids, which can be arranged in any order. Proteins also have four
levels of structure: primary, secondary, tertiary, and quaternary. An alteration in any of these levels
alters the function of the protein. This allows for a large variety of function.
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Enzymes:
1. What occurs during a chemical reaction?
Bonds are broken and reformed; atoms are rearranged.
2. What is the difference between a product and a reactant?
Reactants go in to a chemical reaction; products are formed by a chemical reaction.
3. Energy is used differently in different types of chemical reactions. Explain how energy use differs in
energy-releasing and energy-absorbing reactions. Which type often requires a catalyst? Energyreleasing reactions produce more energy than they require to start, therefore they generally occur
spontaneously
Energy-absorbing reactions require more energy to start than they produce, often requiring large
amounts of activation energy. This often necessitates a catalyst.
4. How is energy related to the products and reactants of a chemical reaction?
Energy is required to break apart the reactants and to form the products.
5. What is the role of an enzyme in living organisms?
Enzymes act as biological catalysts.
6. In what way do enzymes increase the rate of reactions? How do enzymes accomplish this task?
Enzymes provide a location for the reaction to occur. They lower the activation energy needed to start the
reaction, allowing it to occur more quickly.
7. Describe the cycle in which enzymes and substrate interact.
Substrate bonds to the active site of the enzyme. The reaction occurs, converting substrate/reactant into
product. The product is then released. The active site of the enzyme is left unchanged. This allows the
enzyme to continuously catalyze reactions.
8. How/Why is the structure of an enzyme so important to its function in living things? Why does
the structure of an enzyme determine the type of reaction it will catalyze?
The active site of an enzyme is specifically shaped to hold only one specific set of substrates. Enzymes are
therefore substrate specific, meaning they will only catalyze one type of reaction. If the active site of an
enzyme is not designed for a particular substrate, it will not catalyze that reaction.
9. What happens to enzyme function when the temperature or pH conditions change? Why? Changes
in temperature or pH can cause denaturation of the enzyme, changing the shape of the active site and
destroying the function.
10.The energy needed to get a reaction started is the:
B. activation energy
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Bioenergetics
Module A, Anchor 3
Key Concepts:
- ATP can easily release and store energy by breaking and re-forming the bonds between its phosphate
groups. This characteristic of ATP makes it exceptionally useful as a basic energy source for all
cells.
- In the process of photosynthesis, plants convert the energy of sunlight into chemical energy
stored in the bonds of carbohydrates.
- Photosynthetic organisms capture energy from sunlight with pigments.
- An electron carrier is a compound that can accept a pair of high-energy electrons and transfer
them, along with most of their energy, to another molecule.
- Photosynthesis uses the energy of sunlight to convert water and carbon dioxide into high- energy
sugars and oxygen.
- Among the most important factors that affect photosynthesis are temperature, light intensity,
and the availability of water.
- Organisms get the energy they need from food.
- Cellular respiration is the process that releases energy from food in the presence of oxygen.
- Photosynthesis removes carbon dioxide from the atmosphere and cellular respiration puts it back.
Photosynthesis releases oxygen into the atmosphere, and cellular respiration uses that oxygen to
release energy from food.
- In the absence of oxygen, fermentation releases energy from food molecules by producing
ATP.
- For short, quick bursts of energy, the body uses ATP already in muscles as well as ATP made by
lactic acid fermentation.
- For exercise longer than about 90 seconds, cellular respiration is the only way to continue generating
a supply of ATP.
Vocabulary:
ATP
Photosynthesis
Thylakoid
Cellular respiration
Glucose
ADP
pigment
stroma
aerobic
autotroph
chlorophyll
NADP+/NADPH
anaerobic
heterotroph
chloroplast
calorie
fermentation
ATP and Energy Molecules:
1. What are the different energy molecules in the cell? Describe the energy storage capacity of each and
relate this to their function in living organisms.
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2. What are the three parts of an ATP molecule?
A. adenine, thylakoid, and phosphate group
B. stroma, grana, and thylakoid
C. adenine, ribose, and phosphate group
D. NADH, NADPH, and FADH
3. Energy is released from an ATP molecule when:
A. a phosphate group is added
B. a phosphate group is removed
C. adenine bonds to ribose
D. the molecule is exposed to sunlight
4. How do heterotrophs and autotrophs differ in the way they obtain energy?
Photosynthesis:
1. Which organelle is involved in photosynthesis? List and describe the parts of this organelle.
2. Explain what happens to energy during photosynthesis. In what form does it enter photosynthesis? In
what form does it exist during photosynthesis? In what form does it leave photosynthesis? How is this
related to the overall goal of photosynthesis?
3. Plants absorb energy with light-absorbing molecules called:
A. stroma
B. grana
C. thylakoids
D. pigments
4. What is the primary pigment involved in photosynthesis? Why do plants also contain accessory
pigments?
5. A student exposed one plant to only red light and another to only green light. Which should grow better
and why?
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6. Write the basic equation for photosynthesis using the names of the molecules involved. Identify the
products and reactants. Is light a product or reactant? If not, what does it supply to the equation?
7. A student is collecting gas being given off by a plant in direct sunlight. The gas is most likely:
A. water vapor
C. oxygen
B. carbon dioxide
D. ATP
Cellular Respiration and Fermentation:
1. What are the products and reactants of cellular respiration? Where does the reaction take place in
cells?
2. How is energy transformed during cellular respiration? In what form does it enter cellular respiration? In
what form does it leave cellular respiration? How is this related to the overall goal of cellular respiration?
3. What is a calorie? Briefly explain how cells use a high-calorie molecule such as glucose.
4. Compare and contrast photosynthesis and cellular respiration in terms of product, reactant, and energy
transformations in each.
5. Why are photosynthesis and cellular respiration considered opposite reactions?
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7. Compare and contrast fermentation and cellular respiration in terms of product, reactant, and energy
transformations involved.
8. Because fermentation takes place in the absence of oxygen, it is said to be
A. aerobic
B. anaerobic
C. cyclic
D. oxygen-rich
9. In what circumstances is fermentation a better option than cellular respiration and vice versa?
10. Certain bacteria thrive in conditions that lack oxygen. What does that fact indicate about the way they
obtain energy?
11. In certain cases, regular exercise causes an increase in the number of mitochondria in muscle cells. How
might that situation improve an individual’s ability to perform energy-requiring activities?
12. Why must plants contain mitochondria, despite the fact that they can turn light energy into chemical
energy?
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Bioenergetics- ANSWER KEY
Module A Anchor 3
ATP and Energy Molecules:
1. What are the different energy molecules in the cell? Describe the energy storage capacity of each
and relate this to their function in living organisms.
ATP – stores smaller amounts of energy that is easily accessible by the cell. ATP is used to run all cell
activities.
Glucose – stores larger amounts of energy that is more difficult to access. Glucose is used for energy
storage. It is converted into ATP when energy is needed.
2. What are the three parts of an ATP molecule?
C. adenine, ribose, and phosphate group
3. Energy is released from an ATP molecule when:
B. a phosphate group is removed
4. How do heterotrophs and autotrophs differ in the way they obtain energy? Autotrophs
make their own food using energy from the sun or inorganic molecules. Heterotrophs must
consume other organisms for food.
Photosynthesis:
1. Which organelle is involved in photosynthesis? List and describe the parts of this organelle.
Chloroplasts are the organelle of photosynthesis in eukaryotes. The light-dependent reactions occur in the
thylakoid membrane. Stacks of thylakoids are called grana. The light-independent reactions occur in the
stroma.
2. Explain what happens to energy during photosynthesis. In what form does it enter
photosynthesis? In what form does it exist during photosynthesis? In what form does it leave
photosynthesis? How is this related to the overall goal of photosynthesis?
Energy enters photosynthesis as light energy from the sun. During the light-dependent reactions, it is
converted into chemical energy in the form of ATP and electron carriers. These molecules carry the
chemical energy to the light-independent reactions, where it is stored as glucose. The goal of photosynthesis
is to create food from sun energy, thereby converting light energy into a form usable by living organisms.
3. Plants absorb energy with light-absorbing molecules called:
D. pigments
4. What is the primary pigment involved in photosynthesis? Why do plants also contain
accessory pigments?
Chlorophyll – it is a green pigment and therefore cannot absorb light from that part of the electromagnetic
spectrum. Accessory pigments all absorb varying wavelengths of light.
Containing multiple pigments allows plants to absorb the entire spectrum, obtaining more energy for
photosynthesis.
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5. A student exposed one plant to only red light and another to only green light. Which should grow
better and why?
The one under red light. The primary pigment in this plant is likely chlorophyll, which reflects green light.
This prevents the plant from absorbing energy from the light and stunts its growth.
6. Write the basic equation for photosynthesis using the names of the molecules involved. Identify the
products and reactants. Is light a product or reactant? If not, what does it supply to the equation?
Water + carbon dioxide
sugar + oxygen
Reactants – water, carbon dioxide
products – sugar, oxygen Light
supplies energy for the reaction, but is not a product or reactant
7. A student is collecting gas being given off by a plant in direct sunlight. The gas is most likely:
C. oxygen
Cellular Respiration and Fermentation:
1. What are the products and reactants of cellular respiration? Where does the reaction take
place in cells?
 Reactants – sugar, oxygen
Products – carbon dioxide, water Cellular
 respiration takes place in the mitochondria
2. How is energy transformed during cellular respiration? In what form does it enter cellular
respiration? In what form does it leave cellular respiration? How is this related to the overall goal
of cellular respiration?
Energy enters cellular respiration as stored energy in glucose. It leaves cellular respiration as ATP. The goal
of cellular respiration is to provide energy to be used by the cell. Changing from glucose to ATP allows the
energy in glucose to be used by the cell.
3. What is a calorie? Briefly explain how cells use a high-calorie molecule such as glucose.
A calorie is a measure of energy. Cells use high-calorie molecules for energy storage.
4. Compare and contrast photosynthesis and cellular respiration in terms of product, reactant, and
energy transformations in each.
 Photosynthesis –product – sugar, oxygen reactant – water, carbon dioxide
o converts light energy into chemical energy

Cellular respiration – product – water, carbon dioxide, ATP
reactant – sugar, oxygen
o Converts stored chemical energy into usable energy
5. Why are photosynthesis and cellular respiration considered opposite reactions?
The products of one are the reactants of the other.
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7. Compare and contrast fermentation and cellular respiration in terms of product, reactant, and
energy transformations involved.
Cellular respiration and fermentation both start with sugar; however, cellular respiration also requires
oxygen. Cellular respiration produces carbon dioxide, water and energy.
Fermentation produces energy and alcohol or lactic acid. Fermentation produces far less ATP than
cellular respiration.
8. Because fermentation takes place in the absence of oxygen, it is said to be
B. anaerobic
9. In what circumstances is fermentation a better option than cellular respiration and vice versa?
Cellular respiration is a better option in the presence of oxygen, as it produces significantly more energy.
Fermentation is a better option in the absence of oxygen, as cellular respiration cannot take place.
10. Certain bacteria thrive in conditions that lack oxygen. What does that fact indicate about the way
they obtain energy?
They must use fermentation, as cellular respiration requires oxygen.
11. In certain cases, regular exercise causes an increase in the number of mitochondria in muscle cells.
How might that situation improve an individual’s ability to perform energy-requiring activities?
Cellular respiration occurs in the mitochondria, therefore more mitochondria would increase the rate at
which energy could be produced.
12. Why must plants contain mitochondria, despite the fact that they can turn light energy into
chemical energy?
Plants create energy in the form of glucose, which still needs to be converted into ATP.
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Homeostasis and Transport
Module A Anchor 4
Key Concepts:
- Buffers play an important role in maintaining homeostasis in organisms.
- To maintain homeostasis, unicellular organisms grow, respond to the environment, transform
energy, and reproduce.
- The cells of multicellular organisms become specialized for particular tasks and
communicate with one another to maintain homeostasis.
- All body systems work together to maintain homeostasis.
- Passive transport (including diffusion and osmosis) is the movement of materials across the cell
membrane without cellular energy.
- The movement of materials against a concentration differences is known as active transport.
Active transport requires energy.
- The structure of the cell membrane allows it to regulate movement of materials into and out of the
cell. The structure also determines how materials move through the cell membrane.
Vocabulary:
homeostasis
Buffer
Hypertonic
hypotonic
Endocytosis
exocytosis
Plasma membrane
channel proteins
Fluid mosaic model equilibrium
Endoplasmic reticulum
vacuole
diffusion
facilitated diffusion
Concentration gradient
feedback inhibition
multicellular
Golgi apparatus
isotonic
osmosis
feedback mechanism
solute
unicellular
vesicle
Plasma Membrane and Organelles:
1. What is the phospholipid bilayer? How does the structure of a phospholipid relate to its function in
plasma membranes?
2. What is the fluid mosaic model?
3. What are the basic parts of the fluid mosaic model of the plasma membrane? Describe each in terms of
structure and function.
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4. What is the function of the plasma membrane?
5. The cell membrane contains channels and pumps which help in transport. What are these materials
made of?
A. carbohydrate
B. lipid
C. Protein
D. nucleic acid
6. Explain how each of the following organelles is involved in cell transport:
 Vacuoles and vesicles –

Golgi apparatus –

Rough Endoplasmic reticulum –

Smooth Endoplasmic reticulum

Cytoskeleton –
7. Explain the relationship between the endoplasmic reticulum and Golgi apparatus in terms of cell transport.
Transport Mechanisms:
1. How do passive and active transport differ?
2. List and describe the types of passive transport.
3. Why do some molecules require the use of protein channels, as in facilitated diffusion?
4. Diffusion occurs because:
A. molecules are attracted to one another
B. molecules constantly move and collide into one another
C. cellular energy forces molecules to collide with one another
D. cellular energy pumps molecules across the cell membrane
5. During diffusion, when the concentration of molecules on both sides of the membrane is equal,
molecules will:
A. move across the membrane to the outside of the cell
B. stop moving across the membrane
C. continue to move across the membrane in both directions
D. move across the membrane to the inside of the cell
6. Explain equilibrium.
7. What is the relationship between diffusion and osmosis?
8. Compare and contrast hypertonic, hypotonic, and isotonic solutions.
9. Explain, in terms of osmosis, why a raisin placed in a cup of pure water overnight will puff up.
10. Two solutions are placed on either side of a selectively permeable membrane. The membrane is
permeable to solute. There is a higher concentration of solute particles on the left side of the membrane. In
which direction will the solute particles move? Why?
11. List and describe the types of active transport.
12. Compare and contrast endocytosis and exocytosis.
13. How do active transport and facilitate diffusion differ?
Homeostasis:
1. Which of the following activities is NOT a way for unicellular organisms to maintain homeostasis?
A. reproduction
B. growth
C. cell specialization
D. response to environment
2. Explain the relationship between multicellular organisms, cell specialization, and homeostasis.
3. What do unicellular organisms do to maintain homeostasis?
4. The contractile vacuole is an organelle found in paramecia, a group of single-celled organisms.
Contractile vacuoles pump out fresh water that accumulates in the organisms by osmosis. Explain how this
is an example of the way paramecia maintain homeostasis.
5. How do buffers help an organism to maintain homeostasis?
6. In what way are the characteristics of living things related to homeostasis? Obtain and use
materials:

Obtain and use energy:

Grow and develop:

Reproduce:

Respond to environment:
7. What is a feedback mechanism/feedback inhibition? What is the role of a feedback mechanism in
maintaining homeostasis?
8. Briefly explain how animal body systems work together to maintain homeostasis.
Homeostasis and Transport- ANSWER KEY
Module A Anchor 4
Plasma Membrane and Organelles:
1. What is the phospholipid bilayer? How does the structure of a phospholipid relate to its
function in plasma membranes?
The phospholipid bilayer is a double layer of lipids which form into membranes. Phospholipids have a polar
head and a nonpolar tail. The watery environment outside of cells causes the tails to turn in towards each
other, forming a double layer.
2. What is the fluid mosaic model?
A mosaic is a piece of art comprised of many small tiles pieced together. A cell membrane is comprised of
many smaller parts pieced together. It is fluid in that the pieces are not fixed, and can move around within the
membrane.
3. What are the basic parts of the fluid mosaic model of the plasma membrane? Describe each in
terms of structure and function.
 Phospholipid bilayer – forms a barrier around the cell, controls movement into the cell
 Carbohydrate markers – serve as chemical identifiers
 Channels and pumps – function in transport of materials into and out of the cell
4. What is the function of the plasma membrane?
Controls the flow of substances into and out of the cell
5. The cell membrane contains channels and pumps which help in transport. What are these
materials made of?
C. Protein
6. Explain how each of the following organelles is involved in cell transport:
 Vacuoles and vesicles – store materials for transport

Golgi apparatus – modifies, stores, and packages molecules for storage or transport

Rough Endoplasmic reticulum – assembles proteins

Smooth Endoplasmic reticulum – assembles lipids

Cytoskeleton – movement of organelles; scaffold for entire cell
7. Explain the relationship between the endoplasmic reticulum and Golgi apparatus in terms of cell
transport.
The ER makes the proteins and lipids, the Golgi modifies and stores them
Transport Mechanisms:
1. How do passive and active transport differ?
 Active requires cellular energy, passive does not.
2. List and describe the types of passive transport.
 Diffusion – substances move from high to low concentration, passing directly through the
membrane unassisted
 Facilitated diffusion – substances move from high to low concentration, but cannot pass
Directly through the membrane, instead passing through protein channels
 Osmosis –diffusion of water from high to low water concentration, passing directly through the
membrane unassisted
3. Why do some molecules require the use of protein channels, as in facilitated diffusion?
 Charged or large molecules do not dissolve well in the lipid interior of the phospholipid
membrane. They therefore require the use of protein channels.
4. Diffusion occurs because:
B. molecules constantly move and collide into one another
5. During diffusion, when the concentration of molecules on both sides of the membrane is equal,
molecules will:
C. continue to move across the membrane in both directions
6. Explain equilibrium.
In equilibrium, the concentration of solute:solvent is equal on both sides of the membrane. Molecules
continue to move back and forth across the membrane in equal quantities.
7. What is the relationship between diffusion and osmosis?
Osmosis is a type of diffusion, specifically the diffusion of water.
8. Compare and contrast hypertonic, hypotonic, and isotonic solutions.
 Hypertonic solutions have a greater solute concentration than the cell, causing water to move out of
the cell
 Hypotonic solutions have a lower concentration of solution than the cell, causing water to move in to
the cell
 Isotonic solutions have an equal concentration of solute inside and outside the cell, causing no net gain
or loss of water
9. Explain, in terms of osmosis, why a raisin placed in a cup of pure water overnight will puff up.
The water is hypotonic to the raisin, causing water to move into the raisin.
10. Two solutions are placed on either side of a selectively permeable membrane. The membrane is
permeable to solute. There is a higher concentration of solute particles on the left side of the
membrane. In which direction will the solute particles move? Why?
The molecules will move to the right side until equilibrium is reached, then continue to move back and forth
with no net change in concentration. This will occur because the membrane is soluble to solute, which will
move from high to low concentration.
11. List and describe the types of active transport.
 Molecular transport – small molecules move against the concentration gradient through pumps in the
cell membrane

Bulk transport – exocytosis and endocytosis, large materials are moved in or out of the cell via
vesicles.
12. Compare and contrast endocytosis and exocytosis.
 In both instances, the item to be transported is in a vacuole which fuses with the cell membrane.
o In exocytosis, substances are moving out.
o In endocytosis, substances are moving in.
13. How do active transport and facilitated diffusion differ?
Both require protein channels or pumps. However, facilitated diffusion still moves substances from high to
low concentration and does not require energy. Active transport moves from low to high concentration,
requiring energy.
Homeostasis:
1. Which of the following activities is NOT a way for unicellular organisms to maintain
homeostasis?
C. cell specialization
2. Explain the relationship between multicellular organisms, cell specialization, and
homeostasis.
Multicellular organisms are large and complex; therefore, they require more complicated systems in order to
maintain homeostasis. Multicellular organisms accomplish this by designating particular functions to
particular cells. This allows different cells to work together to maintain homeostasis within a larger
organism.
3. What do unicellular organisms do to maintain homeostasis?
Grow, respond to the environment, transform energy, and reproduce.
4. The contractile vacuole is an organelle found in paramecia, a group of single-celled organisms.
Contractile vacuoles pump out fresh water that accumulates in the organisms by osmosis. Explain
how this is an example of the way paramecia maintain homeostasis.
One way in which an organism can NOT maintain a stable environment is through excessive water intake.
Water constantly moves from high to low concentration, thus it is constantly moving into the aquatic amoeba.
The amoeba pumps the water back out to ensure that water concentrations remain stable.
5. How do buffers help an organism to maintain homeostasis?
Prevent rapid changes in pH.
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6. In what way are the characteristics of living things related to homeostasis? Obtain
and use materials:
Obtain materials necessary for life processes

Obtain and use energy:
Energy is required for all cell activities

Grow and develop:
Can develop such things as multicellularity

Reproduce:
Reduces size in unicellular organisms

Respond to environment:
Can obtain needed materials or move from those which threaten to destabilize their internal
conditions
7. What is a feedback mechanism/feedback inhibition? What is the role of a feedback
mechanism in maintaining homeostasis?
Process in which a stimulus produces a response that opposes the original stimulus. The feedback
mechanism corrects the issue which destabilized the internal environment of the organism.
8. Briefly explain how animal body systems work together to maintain homeostasis.
 Nervous system – recognizes and coordinates the body’s responses to changes in internal and external
environments
 Integumentary system - regulates temperature
 Immune/lymphatic system – protects body from disease, maintains fluid balance in circulatory system
 Muscular system – moves blood and food
 Circulatory system – transports oxygen, nutrients, and hormones to cells, removes wastes, fights
infection, helps regulate temperature
 Respiratory system – brings in oxygen and removes excess carbon dioxide Digestive
system – breaks down food, absorbs nutrients, eliminates wastes
 Endocrine system – controls growth, development, and metabolism; maintains homeostasis
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Cell Growth and Reproduction
Module B, Anchor 1
Key Concepts:
- The larger a cell becomes, the more demands the cell places on its DNA. In addition, a larger cell
is less efficient in moving nutrients and waste materials across the cell membrane.
- Asexual reproduction is the production of genetically identical offspring from a single parent.
- Offspring produced by sexual reproduction inherit some of their genetic information from each
parent.
- Chromosomes make it possible to separate DNA precisely during cell division.
- During the cell cycle, a cell grows, prepares for division, and divides to form two daughter
cells.
- During prophase, the genetic material inside the nucleus condenses. During metaphase, the
chromosomes line up across the center of the cell. During anaphase, the chromosomes separate and
move along spindle fibers to opposite ends of the cell. During telophase, the chromosomes, which
were distinct and condensed, begin to spread out into tangle of chromatin.
- The cell cycle is controlled by regulatory proteins both inside and outside the cell.
- Cancer cells do not respond to the signals that regulate the growth of most cells. As a result, the
cells divide uncontrollably.
- The diploid cells of most adult organisms contain two complete sets of inherited
chromosomes and two complete sets of genes.
- In prophase I, replicated chromosomes pair with corresponding homologous chromosomes. At
metaphase I, paired chromosomes line up across the center of the cell. In anaphase I, chromosome
pairs move toward opposite ends of the cell. In telophase I, a nuclear membrane forms around each
cluster of chromosomes. Cytokinesis forms two new cells. As the cells enter prophase II, their
chromosomes become visible. The final four phases of meiosis II result in four haploid daughter
cells.
- In mitosis, when the two sets of genetic material separate, each daughter cell receives one complete
set of chromosomes. In meiosis, homologous chromosomes line up and then move to separate
daughter cells. Mitosis does not normally change the chromosome number of the original cell.
Meiosis reduces the chromosome number by half. Mitosis results in the production of two
genetically identical diploid cells, whereas meiosis produces four genetically different haploid cells.
- Alleles of different genes tend to be inherited together from one generation to the next when those
genes are located on the same chromosome.
Vocabulary:
Cell division
Chromosome
Interphase
Prophase
Centriole
Telophase
asexual reproduction
chromatin
mitosis
centromere
metaphase
cyclin
sexual reproduction
cell cycle
cytokinesis
chromatid
anaphase
growth factor
Cancer
Homologous
tumor
tetrad
apoptosis
crossing-over
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Haploid
diploid
meiosis
Cell Growth, Division, and Reproduction:
1. What are the reasons why cells divide? How does division address these issues?
2. Describe what is meant by each of the following: cell volume, cell surface area, ratio of surface area to
volume. Why is the ratio of surface area to volume important to cell survival?
3. In order for cells to divide successfully, the cell must first
A. duplicate its genetic information
B. decrease its volume
C. increase its number of chromosomes
D. decrease its number of organelles
4. Compare and contrast sexual and asexual reproduction.
5. Which type of reproduction is best suited to a changing environment? Why?
Cell Cycle/mitosis:
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1. List and describe the stages of interphase. Illustrate each description.
2. List and describe the stages of mitosis. Illustrate each stage:
3. If a cell has 12 chromosomes before division, how many chromosomes will be in each of its daughter cells
after mitosis and cytokinesis? Why is this important?
4. Describe how a eukaryotic cell’s chromosomes change as a cell prepares to divide. Why is it
advantageous to package DNA into chromosomes for cell division?
5. What is the relationship between interphase and cell division? Why must the DNA be duplicated
before cell division can occur?
31
6. How is the process of cell division different in prokaryotes and eukaryotes?
7. Compare and contrast cell division in plant and animal cells.
8. What types of cells are produced by mitosis?
Meiosis:
1. List and describe the stages of meiosis I.
2. List and describe the phases of meiosis II.
3. Compare and contrast meiosis I and meiosis II.
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4. What types of cells are produced by meiosis? How do the end products of meiosis differ in males and females?
5. Compare and contrast meiosis and mitosis.
6. What events ensure that the cells produced by mitosis are genetically identical diploids, while the cells
produced by meiosis are genetically different haploids?
7. Why does mitosis produce diploid cells, while meiosis produces haploid cells?
Regulating the Cell Cycle:
1. The timing in the cell cycle in eukaryotic cells is believed to be controlled by a group of closely related
proteins known as:
A. chromatids
B. cyclins
C. centromeres
D. centrioles
2. Compare and contrast internal and external regulators. Give examples of each.
3. How do cancer cells differ from noncancerous cells? How are they similar?
33
4. What is apoptosis? What is the role of apoptosis in regulating the cell cycle?
34
Cell Growth and Reproduction – ANSWER KEY
Module B, Anchor 1
Cell Growth, Division, and Reproduction:
1. What are the reasons why cells divide? How does division address these issues?
Materials Exchange – As cells grown, their volume increases faster than their surface area. This prevents
them from effectively exchanging materials with their environments. Dividing brings the surface area :
volume ratio back into alignment, allowing for more effective exchange of materials.
DNA overload – As the cell grows, the demand on the DNA increases. Dividing decreases the demands on the
DNA.
2. Describe what is meant by each of the following: cell volume, cell surface area, ratio of surface
area to volume. Why is the ratio of surface area to volume important to cell survival?
Cell volume – amount on space inside the cell membrane
Cell surface area – amount of space taken up by cell membrane
Surface area: volume ratio – relationship between the amount of surface area and the amount of
volume. Surface area:volume ratio is related to materials exchange within the cell.
3. In order for cells to divide successfully, the cell must first
A. duplicate its genetic information
4. Compare and contrast sexual and asexual reproduction.
 Both types of reproduction create new organisms.
o Sexual reproduction involves the genetic material of two organisms. It creates new
combinations of alleles not seen in previous organisms. Therefore, it produces offspring with
different physical structures than their parents.
o Asexual reproduction requires only one organism. It produces offspring identical, both
physically and genetically, to their parents.
5. Which type of reproduction is best suited to a changing environment? Why?
Sexual. Sexual reproduction produces offspring with a variety of phenotypes. This allows a greater
chance of survival in a changing environment. If the organisms were produced via asexual reproduction,
they would all be identical. If the environment changed in a way unfavorable to these organisms, they
would all die.
Cell Cycle/mitosis:
1. List and describe the stages of interphase. Illustrate each description.
 G1 phase – normal growth and cell activities S
phase – DNA replication
 G2 phase – cell synthesizes organelles and chemicals needed for division
2. List and describe the stages of mitosis. Illustrate each stage.
 Prophase – Genetic material condenses and becomes visible, nuclear envelope disintegrates, centrioles
begin to move to opposite sides of the cell.
 Metaphase – chromosomes line up in the center of the cell, spindles attach Anaphase –
spindles pull sister chromatids to opposite sides of the cell
 Telophase – nuclear envelop reforms around two new nuclei Cytokinesis – cytoplasm
divides into two identical cells
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3. If a cell has 12 chromosomes before division, how many chromosomes will be in each of its
daughter cells after mitosis and cytokinesis? Why is this important?
12 – so that no DNA is missing from any cell
4. Describe how a eukaryotic cell’s chromosomes change as a cell prepares to divide. Why is it
advantageous to package DNA into chromosomes for cell division?
Chromosomes duplicate and condense. Packaging DNA into chromosomes makes it easier to separate evenly.
5. What is the relationship between interphase and cell division? Why must the DNA be
duplicated before cell division can occur?
Interphase prepares the cell for division. If the DNA was not replicated before division, each daughter cell
would only receive half the appropriate amount of DNA.
6. How is the process of cell division different in prokaryotes and eukaryotes?
In prokaryotes, genetic material is not package in a nucleus. Like in eukaryotes, the DNA duplicates. In then
attached to two different places on the cell membrane. A network of proteins forms between the areas,
pinching in the membrane to divide.
7. Compare and contrast cell division in plant and animal cells.
 Plants – cell wall cannot pinch in, therefore the cell builds a cell plate between the two nuclei

Animal cell – the cell membrane pinches (cleavage furrow) in to form two new cells.
8. What types of cells are produced by mitosis?
Somatic/body cells
Meiosis:
1. List and describe the stages of meiosis I.
 Prophase I – nuclear envelope disintegrates, chromosomes line up in tetrads, crossing-over occurs.
 Metaphase I – chromosomes line up in tetrads across center of cell, spindles attach
 Anaphase I – spindles pull chromosomes to opposite sides of the cell
 Telophase I – nuclear envelopes reform around chromosome sets, producing two haploid neclei
 Cytokinesis – cell splits into two haploid cells
2. List and describe the phases of meiosis II.
 Prophase II – nuclear envelope disintegrates, centrioles move to opposite sides of the cell
 Metaphase II – Chromosomes line up end to end, spindles attach
 Anaphase II – sister chromatids are split and pulled to opposite ends of the cell
 Telophase II – cytoplasm begins to divide, nuclear envelopes form around each nuclei
 Cytokinesis – cell divides into four haploid gametes
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3. Compare and contrast meiosis I and meiosis II.
 Meiosis I – tetrads form, crossing-over occurs, cell begins diploid but ends haploid
 Meiosis II – cells begin and end haploid, no tetrads or crossing-over
4. What types of cells are produced by meiosis? How do the end products of meiosis differ in males
and females?
 Gametes
 Males produce four haploid gametes.
 Females produce one large haploid egg cell and three polar bodies.
5. Compare and contrast meiosis and mitosis.
 Meiosis produces four haploid cells. The cells are not genetically identical to each other or to the
parent cell.
 Mitosis produces two diploid cells. The cells are identical to the parent cell and to each other.
6. What events ensure that the cells produced by mitosis are genetically identical diploids, while the
cells produced by meiosis are genetically different haploids?
 In mitosis, the chromosomes duplicate once and divide once. The chromosomes line up end to end,
so that when they are pulled apart each cell receives a full set of genetic material.
 In meiosis, the chromosomes duplicate once but divide twice. This reduces the amount of genetic
material in each cell by half. When the cells divide the first time, chromosomes line up in pairs instead
of end to end. This ensures that each cell receives half the genetic material.
7. Why does mitosis produce diploid cells, while meiosis produces haploid cells?
 Mitosis is producing replacement body cells, so the cells need a full complement of DNA to function
correctly.
 Meiosis is producing gametes. One gamete is fertilized by another to form offspring, therefore each
must have only half the genetic material needed.
Regulating the Cell Cycle:
1. The timing in the cell cycle in eukaryotic cells is believed to be controlled by a group of closely
related proteins known as:
B. cyclins
2. Compare and contrast internal and external regulators. Give examples of each.
 Internal regulators respond to events inside the cell, such as the duplication of the DNA.
 External regulators respond to events outside the cell, such as contact with other cells.
3. How do cancer cells differ from noncancerous cells? How are they similar?
Cancer cells no longer respond to growth regulators, therefore never stop dividing. Otherwise, they are like
normal body cells.
4. What is apoptosis? What is the role of apoptosis in regulating the cell cycle?
 Programmed cell death.
 Apoptosis plays a key role in removing damaged cells.
37
Genetics
Module B, Anchor 3
Key Concepts:
- An individual’s characteristics are determines by factors that are passed from one parental
generation to the next.
- During gamete formation, the alleles for each gene segregate from each other so that each gamete
carries only one allele for each gene.
- Punnett squares use mathematical probability to help predict the genotype and phenotype
combinations in genetic crosses.
- The principle of independent assortment states that genes for different traits can segregate
independently during the formation of gametes.
- Mendel’s principles of heredity, observed through patterns of inheritance, form the basis of modern
genetics.
- Some alleles are neither dominant nor recessive. Many genes exist in several different forms and
are therefore said to have multiple alleles. Many traits are produced by the interaction of several
genes.
- Environmental conditions can affect gene expression and influence genetically determined
traits.
- The DNA that makes up genes must be capable of storing, copying, and transmitting the genetic
information in a cell.
- DNA is a nucleic acid made up of nucleotides joined into long strands or chains by covalent
bonds.
- DNA polymerase is an enzyme that joins individual nucleotides to produce a new strand of DNA.
- Replication in most prokaryotic cells starts from a single point and proceeds in both directions
until the entire chromosome is copied.
- In eukaryotic cells, replication may begin at dozens or even hundreds of places on the DNA
molecule, proceeding in both directions until each chromosome is completely copied.
- The main differences between DNA and RNA are that (1) the sugar in RNA is ribose instead of
deoxyribose; (2) RNA is generally single-stranded, not double-stranded; and
(3) RNA contains uracil in place of thymine.
- In transcription, segments of DNA serve as templates to produce complementary RNA molecules.
- The genetic code is read three “letters” at a time, so that each “word” is three bases long and
corresponds to a single amino acid.
- Ribosomes use the sequences of RNA codons to assemble amino acids into polypeptide chains.
- The central dogma of molecular biology is that information is transferred from DNA to RNA to
protein.
- Mutations are heritable changes in genetic information.
- The effects of mutations on genes vary widely. Some have little or no effect; some produce
beneficial variations. Some negatively disrupt gene function.
- Mutations often produce proteins with new or altered functions that can be useful to organisms
in different or changing environments.
38
-
-
Human genes follow the same Mendelian patterns of inheritance as the genes of other organisms.
Many human traits follow a pattern of simple dominance. The alleles of other human genes display
codominant inheritance. Because the X and Y chromosomes determine sex, the genes located on
them show a pattern of inheritance called sex- linkage.
Changes in a gene’s DNA sequence can change proteins by altering their amino acid sequences,
which may directly affect one’s phenotype.
If nondisjunction occurs during meiosis, gametes with an abnormal number of
chromosomes may result, leading to a disorder of chromosome numbers.
Recombinant DNA technology – joining together DNA from 2 or more sources – makes it possible
to change the genetic composition of living organisms.
Transgenic organisms can be produced by the insertion of recombinant DNA into the genome of
a host organism.
Ideally, genetic modification could lead to better, less expensive, and more nutrition food as well as
less harmful manufacturing processes.
Recombinant DNA technology is advancing the prevention and treatment of disease.
DNA fingerprinting analyzes sections of DNA that vary widely from one individual to another.
Vocabulary:
Genetics
Trait
Gamete
Homozygous
Multiple allele
Replication
RNA
Transfer RNA
Codon
Biotechnology
Recombinant DNA
DNA fingerprinting
Sex chromosome
fertilization
segregation
probability
heterozygous
polygenic trait
DNA polymerase
messenger RNA
transcription
anticodon
PCR
clone
genome
nondisjunction
allele
hybrid
genotype
codominance
base pairing
nucleotides
ribosomal RNA
polypeptide
translation
genetic marker
plasmid
autosome
principle of dominance
gene
phenotype
independent assortment
Incomplete dominance
nucleic acid
RNA polymerase
genetic code
gene expression
transgenic
gene therapy
sex-linked gene
Basic Mendelian Genetics:
1. Different forms of a gene are called:
A. hybrids
B. dominant factors
C. alleles
D. recessive factors
2. Organisms that have two identical alleles for a particular trait are said to be:
A. hybrid
B. heterozygous
C. homozygous
D. dominant
39
3. What is the difference between a dominant and recessive allele?
4. State the principle of dominance. How does this explain the phenotype of heterozygous organisms?
5. According to this principle, under what conditions will an organism show a recessive phenotype?
6. State the principle of segregation. How does this explain how two heterozygous organisms can
produce homozygous offspring?
7. State the principle of independent assortment.
8. What is a punnett square? How are punnett squares used in genetics?
9. Show the cross between two guinea pigs. One is heterozygous for black color, the other is white.
Record the genotypic and phenotypic ratios of the offspring.
40
Other Patterns of Inheritance:
1. Compare and contrast codominance, incomplete dominance, and complete dominance.
2. Compare and contrast multiple alleles and polygenic traits.
3. Why do multiple alleles and polygenic traits produce many different phenotypes for a trait?
4. Can a trait show more than one inheritance pattern?
5. You would like to determine if a plant shows codominance or incomplete dominance. What type of cross
would you perform and why? Explain how you would know whether the gene involved showed co- or
incomplete dominance.
6. What is the relationship between genes and the environment?
41
DNA Structure:
1. Thoroughly describe the structure of a DNA molecule.
2. What are the base pairing rules? If the percentage of adenine in a sample goes up 5 %, what will happen
to the percentage of thymine? What will happen to the percentage of guanine?
3. What are the three roles of DNA? Explain how the structure of DNA aids in each role.
4. What happens when a piece of DNA is missing?
A. Genetic information is stored
B. Genetic information is transmitted
C. Genetic information is lost
D. Genetic information is copied
DNA Replication:
1. Thoroughly describe the process of DNA replication.
2. Compare and contrast DNA replication in prokaryotes and eukaryotes.
42
3. What is base pairing and how is it involved in DNA replication?
4. When a DNA molecule is replicated, how do the new molecules compare to the original molecule?
How does replication ensure that this occurs?
Transcription:
1. Thoroughly describe the process of transcription.
2. What is made during transcription?
3. Why is transcription necessary for protein synthesis?
4. Suppose you start with a DNA strand ACCGTCACG. Use the rules of base pairing to determine the
complementary RNA strand.
5. Compare and contrast DNA and RNA structure. How does the different structure of RNA relate to its
different function in cells?
6. Compare and contrast DNA replication and transcription.
7. Describe the process of RNA editing.
Protein Synthesis:
1. List the three types of RNA. Describe the role of each in protein synthesis.
2. What is made during protein synthesis?
3. What are codons and anticodons? How do they work together during protein synthesis?
4. Thoroughly describe the process of protein synthesis.
5. Explain why controlling the proteins in an organism controls the organism’s characteristics.
6. What is the correct sequence of transfer of genetic information in most organisms?
A. RNA, DNA, protein
B. DNA, RNA protein
C. protein, DNA, RNA
D. RNA, protein, DNA
7. What are the roles of endoplasmic reticulum and ribosomes in protein synthesis?
8. Does protein synthesis occur in all organisms?
Mutation:
1. What is a mutation?
2. What are some causes of mutation?
3. List and describe the types of gene mutations.
4. What types of gene mutations are most severe? Why?
5. List and describe the types of chromosome mutations.
6. How does the repetitive nature of the genetic code help to reduce the damage done by mutations?
7. One difference between a gene mutation and a chromosomal mutation is
A. A gene mutation affects the DNA of more genes than a chromosomal mutation.
B. A gene mutation can involve as insertion or deletion, but cannot involve a frameshift
C. A chromosomal mutation can affect the number of chromosomes in a cell
D. A chromosomal mutation is more likely to be passed on to offspring or daughter cells
8. Most mutations
A. have no effect on the organism
B. are beneficial
C. are harmful
D. are fatal
Human Heredity:
1. A normal human zygote contains
A. 23 chromosomes
C. 44 chromosomes
B. 46 chromosomes
D. XYY chromosomes
2. What is a nondisjunction? How does a nondisjunction cause chromosome disorders?
3. What is the difference between autosomes and sex chromosomes?
4. What are sex-linked traits? How are they inherited differently between males and females?
5. Which of the following forms a Barr body:
A. one of the Y chromosomes in a male cell
B. one of the X chromosomes in a male cell
C. one of the X chromosomes in a female cell
D. both of the X chromosomes in a female cell
Genetic Engineering:
1. Organisms that contain genes from other organisms are called
A. transgenic
B. mutagenic
C. donors
D. clones
2. Describe what happens during a polymerase chain reaction. What is the use of PCR?
3. Explain what genetic markers are and describe how scientists use them.
4. What are transgenic organisms? What are the potential benefits of transgenic organisms? Concerns?
5. How can genetic engineering impact human health?
6. Describe the uses of DNA fingerprinting.
7. A gene that makes it possible to distinguish a bacterium that has been transformed from one that has not
is:
A. a resistance gene
B. an antibiotic
C. a genetic marker
D. a clone
8. Explain what a DNA probe is and describe how it could be used to identify a person who has an allele for
a genetic disorder.
Genetics- ANSWER KEY
Module B, Anchor 2
Basic Mendelian Genetics:
1. Different forms of a gene are called:
C. alleles
2. Organisms that have two identical alleles for a particular trait are said to be:
C. homozygous
3. What is the difference between a dominant and recessive allele?
A dominant allele shows whenever it is present. A recessive allele shows only if no dominant alleles are
present.
4. State the principle of dominance. How does this explain the phenotype of heterozygous
organisms?
Some alleles are dominant, others are recessive. Heterozygous organisms have one dominant and one
recessive allele. The dominant allele takes over and shows over the recessive allele.
5. According to this principle, under what conditions will an organism show a recessive phenotype?
When no dominant alleles are present, as in tt.
6. State the principle of segregation. How does this explain how two heterozygous organisms can
produce homozygous offspring?
Alleles segregate during the formation of gametes. Each organism contains two alleles for each trait. These
alleles go into different gametes during meiosis. The heterozygous parent has Tt as the genotype. The T
separates from the t when gametes are formed. This allows the T or t to pair up with another letter, giving
homozygous phenotypes.
7. State the principle of independent assortment.
Alleles segregate independently during the formation of gametes.
8. What is a punnett square? How are punnett squares used in genetics?
Punnett squares show the possible offspring of a cross. They are used to predict outcomes of crosses.
9. Show the cross between two guinea pigs. One is heterozygous for black color, the other is white.
Record the genotypic and phenotypic ratios of the offspring.
Black – Tt
T
t
White tt
t
Tt
tt
t
Tt
tt
genotype ratio: 1Tt:1 tt
phenotype ratio:1 black : 1 white
Other Patterns of Inheritance:
1. Compare and contrast codominance, incomplete dominance, and complete dominance.
 Codominance – both alleles are equally dominant, both show up in the heterozygous offspring
 Incomplete dominance – one allele is dominant, but not completely; heterozygous offspring show
a blend of parental traits
 Complete dominance – one allele is completely dominant over the other, heterozygotes show
Dominant trait
2. Compare and contrast multiple alleles and polygenic traits.
 Multiple alleles – one gene controls the trait, more than two alleles exist for the trait
 Polygenic traits – multiple genes control the trait
In both instances, more phenotypes are present than with a more simple inheritance pattern
3. Why do multiple alleles and polygenic traits produce many different phenotypes for a trait?
 Multiple alleles have more options for alleles, producing more phenotypes.
 Polygenic traits show a continuum of traits as they are controlled by multiple genes.
 Any alteration of any allele for any gene results in a slight change in phenotype.
4. Can a trait show more than one inheritance pattern?
Yes. For example, blood type in humans shows multiple alleles, codominance, and complete dominance.
5. You would like to determine if a plant shows codominance or incomplete dominance. What type
of cross would you perform and why? Explain how you would know whether the gene involved
showed co- or incomplete dominance.
Breed the two homozygous plants to get a hybrid plant. If both traits show up, the plant shows codominance.
If a blend shows the plants show incomplete dominance. For example, you breed a red plant and a white
plant. If the hybrid offspring are red with white spots, they show codominance. If the offspring are pink, they
show incomplete dominance.
6. What is the relationship between genes and the environment?
Gene expression is affected by the environment. For example, a set of identical twins may be predisposed
genetically to heart disease. One twin exercises and eats well. They do not develop heart disease due to
their lifestyle. The other twin smokes and eats poorly. They do develop heart disease.
DNA Structure:
1. Thoroughly describe the structure of a DNA molecule.
 DNA is composed of nucleotides; nucleotides are composed of sugar, phosphate, and nitrogenous
base.
 DNA has a double helix shape.
 The sides of the helix are sugar-phosphate backbone. They are composed of deoxyribose and
phosphate.
 The “rungs” of the helix are composed of base pairs. Adenine bonds with thymine and cytosine with
guanine.
 The two sides of the molecule run antiparallel. The sides are held together with covalent bonds.
 The base pairs are held together with hydrogen bonds.
2. What are the base pairing rules? If the percentage of adenine in a sample goes up 5 %, what will
happen to the percentage of thymine? What will happen to the percentage of guanine?
 Adenine – thymine
 Cytosine – guanine
 Thymine will also go up 5%. Guanine will go down 5%.
3. What are the three roles of DNA? Explain how the structure of DNA aids in each role.
Store information – stores information in the sequence of the base pairs
Copy and transmit information – the hydrogen bonds between bases break easily, exposing the bases to be
copied. The covalent bonds hold the two sides together during replication. This allows the molecule to be
copied and passed on to offspring.
4. What happens when a piece of DNA is missing?
C. Genetic information is lost
DNA Replication:
1. Thoroughly describe the process of DNA replication.
The DNA molecule is unwound. The hydrogen bonds between the bases are broken. Enzymes match up bases
according to the base-pairing rules. The leading and lagging strands are assembled in opposite directions.
Once the strands are fully replicated, the new DNA molecules are proof-read.
2. Compare and contrast DNA replication in prokaryotes and eukaryotes.
 In prokaryotes, DNA replication starts at a single point and proceeds in both directions.

In eukaryotes, replication starts in multiple locations.
3. What is base pairing and how is it involved in DNA replication?
A=T C=G This ensures that the two DNA strands are identical, as A must bond with T and C must bond
with G.
4. When a DNA molecule is replicated, how do the new molecules compare to the original
molecule? How does replication ensure that this occurs?
Each new molecule is comprised of one new strand and one original strand. The two molecules are identical
to each other and to the template strand. Since the old molecule is used as a template and the base-pairing
rules must be followed, the strands are identical.
Transcription:
1. Thoroughly describe the process of transcription.
The DNA strand is unwound starting at the promoter region. RNA polymerase binds to the promoter
region on one DNA strand and begins matching base pairs. This continues until the termination sequence
is reached. The RNA strand breaks off the DNA and the DNA reforms. The RNA is then edited.
2. What is made during transcription?
RNA
51
3. Why is transcription necessary for protein synthesis?
Each DNA molecule contains many genes, each coding for a different protein. RNA contains only the gene
for one protein. Also, DNA does not leave the nucleus. Protein synthesis occurs in the cytoplasm. RNA is
capable of traveling to the cytoplasm for protein synthesis.
4. Suppose you start with a DNA strand ACCGTCACG. Use the rules of base pairing to
determine the complementary RNA strand.
UGGCAGUGC
5. Compare and contrast DNA and RNA structure. How does the different structure of RNA
relate to its different function in cells?
 Both –made of nucleotides; contain phosphate, adenine, cytosine, guanine
 RNA – contains ribose and uracil; single-stranded; only one gene
 DNA – contains deoxyribose and thymine; double stranded, many genes
6. Compare and contrast DNA replication and transcription.
 Both – DNA is unwound and bases are added
 Replication – entire molecule is copied; template strand becomes part of new molecules
 Transcription – only part of one strand is copied; template strand rejoins and is left as it was
7. Describe the process of RNA editing.
RNA is cut into introns and exons. Exons are used to create final RNA molecule. The same RNA strand can
be cut and rejoined in multiple ways, producing different final RNA from the same original molecule.
Protein Synthesis:
 List the three types of RNA. Describe the role of each in protein synthesis.
Messenger RNA – carries the message from DNA to be used to create proteins
 Ribosomal RNA – makes up ribosomes, the site of protein synthesis
 Transfer RNA – reads the mRNA and matches up complementary amino acids
1. What is made during protein synthesis?
protein
2. What are codons and anticodons? How do they work together during protein synthesis?
Codons – sequences of three bases on mRNA
Anticodon – sequence of three bases on tRNA complementary to mRNA codon
The anticodons and codons are complementary to each other. The tRNA matches up with the mRNA. On the
opposite end of the tRNA is an amino acid. This is how the tRNA translates the mRNA into an amino acid
sequence.
3. Thoroughly describe the process of protein synthesis.
The mRNA is transcribed in the nucleus. It travels to the cytoplasm, where it binds to the ribosome. The
mRNA moves through the A and P sites of the ribosome. The tRNA molecules
match up with the exposed codons on the mRNA. The amino acids on the other end of each tRNA bind
together to form a polypeptide. When the stop codon is reached, the polypeptide is released.
52
4. Explain why controlling the proteins in an organism controls the organism’s characteristics.
Proteins determine all of our traits. The order of amino acids in a protein determine how it functions. Any
alteration in a protein will result in a change of loss of function for the characteristic it controls in the
organism.
5. What is the correct sequence of transfer of genetic information in most organisms?
B. DNA, RNA protein
6. What are the roles of endoplasmic reticulum and ribosomes in protein synthesis?
Rough ER houses ribosomes. Ribosomes are the site of protein synthesis. The rough ER also modifies
proteins after translation.
7. Does protein synthesis occur in all organisms?
Yes.
Mutation:
1. What is a mutation?
A heritable change in the genetic material of an organism.
2. What are some causes of mutation?
Carcinogens, mistakes in replication, etc.
3. List and describe the types of gene mutations.
 Substitution – one base is switched for another
 Insertion – one base is added to the sequence
 Deletion – one base is removed from the sequence
o Insertion and deletion mutations fall into the category of frameshift mutations.
4. What types of gene mutations are most severe? Why?
Frameshift mutations alter more codons, and thus have a more severe effect on the function of the protein. If
substitution mutations result in a stop codon they are also severe.
5. List and describe the types of chromosome mutations.
 Deletion – gene deleted
 Duplication – extra copy of gene included
 Inversion – gene order is reversed
 Translocation – genes from nonhomologous chromosomes are switched
6. How does the repetitive nature of the genetic code help to reduce the damage done by mutations?
Multple codons code for the same amino acid. Therefore, a mutation may change a base without changing
the amino acid for which that codon codes. This would result in no change in the protein function.
7. One difference between a gene mutation and a chromosomal mutation is
C. A chromosomal mutation can affect the number of chromosomes in a cell
8. Most mutations
A. have no effect on the organism
53
Human Heredity:
1. A normal human zygote contains
B. 46 chromosomes
2. What is a nondisjunction? How does a nondisjunction cause chromosome disorders?
Nondisjunction occurs when the chromosomes fail to separate properly during meiosis. This results in a
gamete having too many or too few of a particular chromosome. If this gamete is fertilized, the resulting
organism will have a chromosome disorder.
3. What is the difference between autosomes and sex chromosomes?
Sex chromosomes determine gender. Autosomes are all the remaining chromosomes.
4. What are sex-linked traits? How are they inherited differently between males and females?
Traits on the x chromosome. Males have one x chromosome, while females have two. This means that a
male will show any trait on its X, even a recessive one. Females still require two copies of the recessive X
to show such a trait. Therefore, x-linked traits are more common in males than in females.
5. Which of the following forms a Barr body:
C. one of the X chromosomes in a female cell
Genetic Engineering:
1. Organisms that contain genes from other organisms are called
A. transgenic
2. Describe what happens during a polymerase chain reaction. What is the use of PCR?
The first step in using the polymerase chain reaction method to copy a gene is to heat a piece of DNA, which
separates its two strands. Then, as the DNA cools, primers bind to the single strands. Next, DNA
polymerase starts copying the region between the primers. These copied can serve as templates to make still
more copies.
3. Explain what genetic markers are and describe how scientists use them.
A gene that makes it possible to distinguish bacteria that carry a plasmid from those that don’t carry it.
Scientists use genetic markers to determine if a transgenic attempt was successful.
4. What are transgenic organisms? What are the potential benefits of transgenic organisms?
Concerns?
 Organisms that contain genetic material from other species.
 Transgenic organisms may improve agricultural yields, reduce pesticide use, manufacture human
proteins, etc.
 There is some fear over unintended side-effects. For example, crops may spread pesticide resistance
to weed species. Allergic reactions or other illnesses may occur, transgenic organisms are patented
which reduces the free nature of food supplies, etc.
5. How can genetic engineering impact human health?
Genetic engineering could help produce human proteins for use in medicine. There is also some concern
over an increase in disease or allergies.
6. Describe the uses of DNA fingerprinting.
Establishing family relationships, crime scenes, etc.
54
7. A gene that makes it possible to distinguish a bacterium that has been transformed from one that
has not is:
C. a genetic marker
8. Explain what a DNA probe is and describe how it could be used to identify a person who has an
allele for a genetic disorder.
Small segments of DNA that help locate a particular gene in a long DNA sequence. They could be used to
analyze the individual’s DNA to determine the presence, or lack therof, of a gene.
55
Ecology
Module B, Anchor 4
Key Concepts:
- The biological influences on organisms are called biotic factors. The physical components
of an ecosystem are called abiotic factors.
- Primary producers are the first producers of energy-rich compounds that are later used by other
organisms. Organisms that rely on other organisms for energy and nutrients are called consumers.
- Energy flows through an ecosystem in a one-way stream, from primary producers to various
consumers. Pyramids of energy show the relative amount of energy available at each trophic level
of a food chain or food web. A pyramid of biomass illustrates the relative amount of living organic
matter available at each trophic level of an ecosystem. A pyramid of numbers shows the relative
number of organisms at each tropic level in an ecosystem.
- Unlike the one-way flow of energy, matter is recycled within and between ecosystems. Water
continuously flows between the oceans, the atmosphere, and land – sometimes outside organisms
and sometimes inside organisms. Every organism needs nutrients to build tissues and carry out life
functions. Like water, nutrients pass through organisms and the environment through
biogeochemical cycles. The carbon, nitrogen, and phosphorus cycles are particularly important for
life.
- A region’s climate is defined by year-after-year patterns of temperature and precipitation.
Global climate is shaped by many factors, including solar energy trapped in the biosphere, latitude,
and the transport of heat by winds and ocean currents.
- A niche is the range of physical and biological conditions in which a species lives and the way the
species obtains what it needs to survive and reproduce.
- By causing species to divide resources, competition helps determine the number and kinds of
species in a community and determine the number and kinds of species in a community and the
niche each species occupies.
- Predators can affect the size of prey populations in a community and determine the places prey can
live and feed. Herbivores can affect both the size and distribution of plant populations in a
community and can determine the places certain plants can survive and grow.
- Biologists recognize three main classes of symbiotic relationships in nature: mutualism, parasitism,
and commensalism.
- Ecosystems change over time, especially after disturbances, as some species die out and new species
move in. Secondary succession in healthy ecosystems following natural disturbances often
reproduces the original climax community. Ecosystems may or may not recover from human
disturbances.
- Biomes are described in terms of abiotic factors like climate and soil type, and biotic factors like
plant and animal life.
- Ecologists typically divide the ocean into zones based on depth and distance from shore.
- The factors that can affect population size are the birthrate, the death rate, and the rate at which
individuals enter or leave the population.
56
-
-
-
Under ideal conditions with unlimited resources, a population will grow exponentially. Logistic
growth occurs when a population’s growth slows and then stops, following a period of exponential
growth.
Acting separately or together, limiting factors determine the carrying capacity of an
environment for a species.
Birthrates, death rates, and the age structure of a population help predict why some countries
have high growth rates while other countries grow more slowly.
Humans affect regional and global environments through agriculture, development, and industry in
ways that have an impact on the quality of Earth’s natural resources, including soil, water, and the
atmosphere. Sustainable development provides for human needs while preserving the ecosystems
that produce natural resources.
Biodiversity’s benefits to society include contributions to medicine and agriculture, and the
provision of ecosystem goods and services. Humans reduce biodiversity by altering habitats,
hunting, introducing invasive species, releasing pollution into food webs, and contribution to
climate change.
Vocabulary:
Biosphere
population
biome
primary producer
carnivore
decomposer
trophic level
Nutrient
limiting nutrient
microclimate
resource
Herbivory
keystone species
mutualism
Succession
pioneer species
estuary
emigration
limiting factor
monoculture
deforestation
Pollutant
smog
Biodiversity
genetic diversity
Ecosystem diversity species diversity
Extinction
Chemosynthesis
community
ecology Ecosystem
biotic factor
abiotic factor Autotroph
photosynthesis
heterotroph Consumer
herbivore
scavenger Omnivore
detritivore
food chain Food web
ecological pyramid biomass
weather
Biogeochemical cycle Climate
tolerance
greenhouse effect Habitat niche
predation
competitive exclusion principle Symbiosis
parasitism
commensalism
primary succession secondary succession Wetland
population density
age structure Immigration
exponential growth logistic growth Carrying capacity
global warming
ecological hot spot Demography
Renewable resource desertification Ecological footprint
acid rain
nonrenewable resource
habitat fragmentation sustainable development
ozone layer
biological magnification
density-dependent limiting factor
density-independent limiting factor
Energy Flow in Ecosystems:
1. What is a trophic level? List and describe the different trophic levels in ecosystems.
2. How do producers and consumers differ in how they obtain energy?
57
3. Describe how energy moves through an ecosystem. How is energy lost from ecosystems? What rule
describes this loss?
4. What is the ultimate source of all energy on Earth?
5. Compare and contrast food webs and food chains.
6. Compare energy pyramids, biomass pyramids, and pyramids of numbers in terms of the information
they give about ecosystems.
Biogeochemical Cycles:
1. Compare and contrast the movement of energy and matter in ecosystems.
2. List the steps of the water cycle. Which steps add water to the atmosphere? Which steps remove it?
3. List the steps of the carbon cycle. Which steps add carbon to the atmosphere? Which steps remove it?
58
4. How is the carbon cycle related to climate change?
5. List the steps of the nitrogen cycle. What makes nitrogen available to living things?
6. Describe the phosphorus cycle.
7. What is nutrient limitation?
Climate and Climate Change:
1. What factors influence global climate? Describe each.
2. How do climate and weather differ?
3. What is the greenhouse effect? Why is it so vital to life on Earth?
4. What are the possible natural causes of global climate change?
5. What are the possible human causes of global climate change?
6. What is the evidence for global climate change?
7. What are the potential impacts of climate change?
Ecosystems and Communities:
1. What is a niche? What factors define a niche? How is it different from a habitat?
2. What is competition? How does competition affect the niche of an organism?
3. How do predation and herbivory affect prey/plant populations?
4. What is a keystone species? Why is the elimination of keystone species of such concern?
5. List and describe the types of symbiotic interactions between organisms.
6. What is succession? Describe the steps involved in both types of succession?
7. List the major biomes. What are the factors used to define a biome?
Population Growth:
1. Describe the different factors used to study populations.
2. What four factors affect the size of a population? Which increase it? Which decrease it?
3. Compare and contrast exponential and logistic growth.
4. What is a limiting factor? Compare and contrast density-dependent and density-independent limiting
factors.
5. If a limiting factor was increased, what would happen to the population over time? Why?
6. What is carrying capacity? How is carrying capacity related to limiting factors?
7. What is the trend of human population growth over time? What challenges does this present for global
ecosystems?
Humans and the Environment:
1. Compare and contrast renewable and nonrenewable resources. Provide examples of each.
2. Describe several problems associated with human resources use.
3. Describe several problems associated with agriculture.
4. Describe several problems related to increased human development.
Ecology- ANSWER KEY
Module B, Anchor 4
Energy Flow in Ecosystems:
1. What is a trophic level? List and describe the different trophic levels in ecosystems.
 A trophic level indicates the energy flow within and ecosystem.
 Producers are the initial level. They convert light or chemical energy into a form usable by other
organisms.
 Primary consumers get their energy from producers.
 Secondary consumers get their energy from primary consumers.
 Tertiary from secondary, quaternary from tertiary, etc.
 Organisms can occupy multiple trophic levels. For example, an omnivore eats both plants and
herbivorous mammals.This omnivore is both a primary and secondary consumer.
2. How do producers and consumers differ in how they obtain energy?
 Producers make their own food using energy from the sun or from inorganic chemicals.
 Consumers ingest other organisms for food.
3. Describe how energy moves through an ecosystem. How is energy lost from ecosystems? What
rule describes this loss?
 Energy flows through an ecosystem from producers through upper level consumers.

Energy is lost as heat or is used for work. The 10% rule governs this: only 10% of the energy in one
trophic level moves to the next.
4. What is the ultimate source of all energy on Earth?
sun
5. Compare and contrast food webs and food chains.
 A food chain shows one simplistic set of feeding relationships.
 A food web shows all the interacting feeding relationships in a community.
6. Compare energy pyramids, biomass pyramids, and pyramids of numbers in terms of the
information they give about ecosystems.
 An energy pyramid shows the amount of energy in each trophic level.
 A biomass pyramid shows the amount of biomass.
 A pyramid of numbers shows the numbers of organisms in each trophic level.
Biogeochemical Cycles:
1. Compare and contrast the movement of energy and matter in ecosystems.
 Energy flows and must be constantly replenished by the sun.
 Matter cycles.
2. List the steps of the water cycle. Which steps add water to the atmosphere? Which steps
remove it?
 Evaporation and transpiration add water to the atmosphere.
 Precipitation removes water from the atmosphere.
 Water exists on the ground as runoff, groundwater, and in bodies of water.
3. List the steps of the carbon cycle. Which steps add carbon to the atmosphere? Which steps
remove it?
 Carbon enters the atmosphere through burning of fossil fuels, diffusion out of oceans, and
respiration.
 Carbon leaves the atmosphere through the creation of fossil fuels, diffusion into oceans, and
photosynthesis.
4. How is the carbon cycle related to climate change?
 Climate change is caused by an accumulation of greenhouse gases, such as carbon dioxide. The
acceleration of carbon releasing activities without a balancing quantity of carbon absorbing activities
can accelerate climate change.
5. List the steps of the nitrogen cycle. What makes nitrogen available to living things?
 Nitrogen is removed from the atmosphere through nitrogen fixation, which includes nitrification and
ammonification. Nitrogen fixation can also occur atmospherically, through lightening.
 Denitrifying bacteria return nitrogen to the atmosphere. Nitrogen must be fixed by bacteria in order
to be made available to living things.
6. Describe the phosphorus cycle.
 Phosphorus does not enter the atmosphere, but moves through the other portions of the Earth.
 Phosphorus weathers from rocks and minerals and is washed into bodies of water by runoff.
 It is also taken up by plants, which are eaten and incorporated into the bodies of animals.
 Decaying organic material returns phosphorus to the soil
7. What is nutrient limitation?
 Organisms need particular nutrients to grow. A nutrient that is not present in sufficient amounts is
said to be limiting, in that it limits the ability of the organism to grow.
Climate and Climate Change:
1. What factors influence global climate? Describe each.
 Angle of solar radiation- a more direct angle of solar radiation increases the amount of energy
absorbed. Therefore, areas of the Earth near the equator receive much more solar radiation than
the poles.
 Wind – redistributes heat from solar radiation across the globe. Warm air rises and holds more
moisture. Cool air falls and is drier. This creates Hadley cells, which produce predictable strips of
biomes across the globe.
 Ocean currents – also redistribute solar radiation. Can have a large modifying effect on the
landmasses by which they pass.
2. How do climate and weather differ?
 Climate – long-term averages
 Weather – day to day temperature and precipitation
3. What is the greenhouse effect? Why is it so vital to life on Earth?
The Earth’s atmosphere consists largely of greenhouse gases. As solar radiation strikes Earth, it is reflected
back into space. Greenhouse gases bounce the reflected radiation back to Earth,allowing the Earth to warm.
Without the greenhouse effect, Earth would not be warm enough to sustain life.
4. What are the possible natural causes of global climate change?
Altering patterns of solar irradiance.
5. What are the possible human causes of global climate change?
Increased emissions of greenhouse gases, clearing of the land for human activities
6. What is the evidence for global climate change?
Ice cores, global temperature data, satellite imagery, increase in sea temperatures, rising sea levels, retreat of
arctic ice, shrinking ice sheets, glacial retreat, ocean acidification, increase in extreme weather events
7. What are the potential impacts of climate change?
Rising sea levels, significantly altered climate (not just hotter, but an alteration overall. Some areas are
currently kept Warmer than they would normally be due to ocean currents, which could be altered due to
climate change), droughts, increase in extreme weather, increased disease, decreased availability of fresh
water
Ecosystems and Communities:
1. What is a niche? What factors define a niche? How is it different from a habitat?
 Niche = The role and needs of an organism in an ecosystem.
 Physical and biological factors influence a niche.
 A habitat simply describes the needs of an organism, without addressing what the organism does
within the community.
2. What is competition? How does competition affect the niche of an organism?
 Organisms which have similar needs will often compete for resources.
 Two organisms cannot occupy the same niche within the same community. Therefore, organisms with
the same needs and role may occupy different locations within the ecosystem or have other
compensatory mechanisms to reduce competition.
3. How do predation and herbivory affect prey/plant populations?
They affect the population size and distribution of prey/plant species.
4. What is a keystone species? Why is the elimination of keystone species of such concern?
 Keystone species = A species that has an effect on the environment disproportionate to its abundance.
 If the species is eliminated, it may cause the collapse of the community.
5. List and describe the types of symbiotic interactions between organisms.
 Parasitism – one species benefits, the other is harmed
 Commensalism – one species benefits, the other is unaffected
 Mutualism – both species benefit
6. What is succession? Describe the steps involved in both types of succession?
 Succession is the orderly process of restoration in a community after creation or new
disturbance.
 Primary succession – bare rock colonized by pioneer species, then grass, then shrubs, then trees,
then climax community
 Secondary succession – disturbance wipes out existing community, grass, shrubs, trees, climax
community
7. List the major biomes. What are the factors used to define a biome?
 Desert, tundra, tiaga, tropical forest, temperate forest, boreal forest, savanna, temperature grassland.
 Temperature, precipitation, species present.
Population Growth:
1. Describe the different factors used to study populations.
Geographic range, density, distribution, growth rate, age structure
2. What four factors affect the size of a population? Which increase it? Which decrease it?
 Increase: immigration, birth
 Decrease: emigration, death
3. Compare and contrast exponential and logistic growth.
 Exponential –starts out slowly, then rapidly increases without end
 Logistic – increases to a point, then levels off
Both start with a similar pattern.
4. What is a limiting factor? Compare and contrast density-dependent and density-independent
limiting factors.
 Limiting factor = Something needed by an organism which is not present in sufficient amounts,
limiting the growth of that organism.
 Density-dependent factors depend on the amount of organisms living in an area, density-independent
factors do not.
5. What is carrying capacity? How is carrying capacity related to limiting factors?
 The number of organisms which can be supported by an ecosystem.
 Limiting factors determine the carrying capacity of an area, as running out of a limiting factor will
cause a group to reach carrying capacity.
6. If a limiting factor was increased, what would happen to the population over time? Why?
It would begin to increase in size again, as the item limiting its growth was no longer in short supply.
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