QUIZ 1:
1. Which of the following structural level of a protein is LEAST affected by a disruption in
hydrogen bonding?
a. Primary Structure!
b. Why? The primary structure is held together by covalent bonds such as peptide
bonds. Everything else has hydrogen bonds.
2. Imagine two hypothetical enzymes, Enzyme 1 and Enzyme 2. Enzyme 1 has more hydrogen
bonds between its side chains than Enzyme 2. Based on this info alone, what can you
conclude?
a. Enzyme 1 would denature at a HIGHER temperature compared to Enzyme 2
b. Why? More hydrogen bonds make it harder to denature the enzyme because it gets
stronger, so it would take more energy to break the bond.
3. Two alpha helices interacting with each other or an alpha helix interacting with a betapleated sheet within a single polypeptide is an example of a protein’s:
a. Tertiary Structure
b. The tertiary structure will have a single polypeptide chain "backbone" with one or
more protein secondary structures.
i. Primary structure: the linear arrangement of amino acids in a protein and
the location of covalent linkages such as disulfide bonds between amino
acids.
ii. Secondary structure: areas of folding or coiling within a protein; examples
include alpha helices and pleated sheets, which are stabilized by hydrogen
bonding.
iii. Tertiary structure: the final three-dimensional structure of a protein, which
results from a large number of non-covalent interactions between amino
acids.
iv. Quaternary structure: non-covalent interactions that bind multiple
polypeptides into a single, larger protein.
4. Fats differ from phospholipids in:
a. The number of fatty acids and hydrophobicity
b. Why? Triglycerides have 3 fatty acids and are hydrophobic. Phospholipids have 2
fatty acids and have a hydrophobic and hydrophilic part.
5. The breakdown of polymers to form monomers results from:
a. Hydrolysis reactions
b. Why? Polymers are broken down into monomers in a process known as hydrolysis,
which means "to split water," a reaction in which a water molecule is used during the
breakdown
6. Which of the following could have hormonal function?
a. Steroids and proteins
b. Why? Some proteins function as chemical-signaling molecules called hormones.
These proteins are secreted by endocrine cells that act to control or regulate specific
physiological processes, which include growth, development, metabolism, and
reproduction.
i. Steroids = estrogen, testosterone, etc. (cholesterol is steroid’s parent
compound)
7. Which of the following macromolecules would most likely exhibit radioactivity from
phosphorus incorporation?
a. Phospholipids and nucleic acids
8. Which of the following structures would most likely exhibit radioactivity from phosphorus
incorporation?
a. Plasma membrane, nucleus, and endoplasmic reticulum
9. Plant cells contain which of the following:
a. Chloroplasts, mitochondria, cell wall
10. Which of the following is present in a prokaryotic cell?
a. Ribosome
11. Know null hypothesis, chi square, and p
a. P value over .05 = accept the null hypothesis, and assume that there is no statistical
reason why any variation occurs (result likely by chance)
QUIZ 2:
1. According to the fluid mosaic model of cell membranes, which of the following is a true
statement about membrane phospholipids?
a. True: they can move laterally along the plane of the membrane
b. Why? Model explains various observations regarding the structure of functional cell
membranes
i. describes the cell membrane as a two-dimensional liquid that restricts the
lateral diffusion of membrane components
2. Which of the following is one of the ways that the membranes of winter wheat are able to
remain fluid when it is extremely cold?
a. By increasing the percentage of unsaturated phospholipids in the membrane.
b. Why? Increasing unsaturated phospholipids, increasing cholesterol in the membrane
i. If unsaturated fatty acids are compressed, the "kinks" in their tails push
adjacent phospholipid molecules away, which helps maintain fluidity in the
membrane
ii. Cholesterol functions as a buffer, preventing lower temperatures from
inhibiting fluidity and preventing higher temperatures from increasing
fluidity.
3. Which of the following is a characteristic feature of a carrier protein in a plasma membrane?
a. It exhibits a specificity for a particular type of molecule
b. Why? A protein that transports specific substance through intracellular
compartments, into the extracellular fluid, or across the cell membrane
4. What kinds of molecules pass through a cell membrane most easily?
a. Small hydrophobic
5. Which of the following statements about diffusion is correct?
a. It is a passive process in which molecules move from a region of higher concentration
to a region of lower concentration
6. A primary function of polysaccharides attached to glycoproteins and glycolipids of animal
cell membranes is to:
a. mediate cell-to-cell recognition
7. Mammalian blood contains the equivalent of .15 M NaCl. Seawater contains the equivalent
of .45 M NaCl. What will happen if red blood cells are transferred to seawater?
a. Water will leave the cells, causing them to shrivel and collapse.
b. Why? The high concentration of salt outside of the cell will make the cell attempt to
be isotonic; the water will leave the cell to make the concentrations equal, causing the
cells to shrivel and DIE
8. Celery stalks that are immersed in fresh water for several hours become turgid (stiff). Celery
stalks left in a .15 M salt solution become flaccid (limp). From this we can deduce that
a. The fresh water is hypotonic and the salt solution is hypertonic to the cells of the
celery stalks
b. Why? Celery stalks have higher concentration of salt than fresh water, but a lower
concentration than the salt solution.
9. Which of the following membrane activities requires energy from ATP hydrolysis?
a. Movement of sodium ions from a lower concentration in a mammalian cell to a
higher concentration in the extracellular fluid
b. Why? Low to high concentration is AGAINST the concentration gradient
10. The primary function of phosphatases in signal transduction is to
a. Inactivate protein kinases to turn off signal transduction
b. Why? phosphatase is an enzyme that removes a phosphate group from a protein
11. Which of the following enzymes adds a phosphate group to target proteins?
a. Kinase
b. Why? Opposite of phosphatase, turns on signal transduction
12. Which of the following is true of steroid receptors?
a. The receptor molecules may be soluble proteins in the cytoplasm
13. Which of the following correctly describes the relationship between an enzyme and its
function?
a. Phosphatase: removal of a phosphate group
14. Which of the following is the greatest advantage of having multiple steps in a transduction
pathway?
a. Having multiple steps provides for greater amplification of a signal
15. The primary function of kinases in signal transduction is to
a. Activate protein or other relay molecules in a series
16. Following activation of a receptor, which sequence below represents the correct order in
which components will be involved in a signaling pathway that utilizes the second messenger
cAMP?
a. G protein  adenylyl cyclase  cAMP
17. Which of the following in the figure is cholesterol?
a. E (it’s within the phospholipid bilayer)
18. Which component in the figure is a peripheral protein?
a. D (protein outside of the cell)
19. Which line or lines in the graph in the figure represent(s) bags that contain a solution that is
hypertonic at 50 minutes?
a. A and B
b. Why? bag has a higher concentration after 50 minutes because the bag is hypertonic
to the cell because the hypertonic solution will send stuff into the bag (high
concentration to low concentration)
20. Which line in the graph represents the bag that contained a solution isotonic to the .6 M
solution at the beginning of the experiment?
a. C (does not change)
Quiz 3:
1. When chemical, transport, or mechanical work is done by an organism, what happens to heat
generated?
a. It is released to the environment
2. The deltaG for a particular enzyme-catalyzed reaction is -20 kcal/mol. If the amount of
enzyme in the reaction is doubled, what will be the deltaG for the new reaction?
a. -20 kcal/mol
b. why? enzymes only lower activation energy, but do not change the difference
in energy levels between reactants and products.
3. In figure 6.2, why does the reaction rate plateau at higher reactant concentration?
a. Most enzyme molecules are occupied by substrate at high reactant concentrations
i. You can only add so much before it is saturated with reactant
4. In an oxidation-reduction reaction (such as that occurs in glycolysis), the molecule that is
reduced:
a. Gains electrons and gains potential energy
5. The complete reactions of cellular respiration in the presence of oxygen (C6H12O6 (s) + 6
O2 (g) → 6 CO2 (g) + 6 H2O (l) + energy) result in which of the following?
a. Oxidation of C6H12O6 and reduction of O2
6. Which of the following statements about NAD+ is true?
a. NAD+ is reduced to NADH during glycolysis
7. In animal cells, glycolysis occurs in the
a. Cytosol
8. How many carbons are released as CO2 during the citric acid cycle per glucose molecule?
a. 4
9. The oxygen consumed during cellular respiration is involved most directly in which process
or event?
a. Accepting electrons at the end of the electron transport chain
10. The complete oxidation of glucose in aerobic respiration occurs through which of the
following sequences of metabolic reactions?
a. Glucose  glycolysis  pyruvate oxidation  citric acid cycle  electron transport
chain
11. During glycolysis, when each molecule of glucose is catabolized to two molecules of
pyruvate, MOST of the potential energy contained in glucose is
a. Retained in the two pyruvates
b. Why? pyruvate retains more of the energy since the pyruvate moves on to the krebs
cycle where more ATP, FADH2, and NADH is produced
12. Starting with one molecule of glucose, the net energy-containing products of glycolysis are
a. 2NADH, 2 pyruvates, and 2 ATP
13. Why is glycolysis described as having an energy investment phase and an energy payoff
phase?
a. Early steps consume energy from ATP, and later steps store an increased amount of
energy in ATP and NADH.
14. How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one
molecule of pyruvate?
a. 2
15. Carbon dioxide (CO2) is released during which of the following stages of cellular
respiration?
a. Oxidation of pyruvate to acetyl CoA and the citric acid cycle
16. How many molecules of FADH2 are generated after one molecule of acetyl CoA goes
through the citric acid cycle?
a. 1
17. Inside an active mitochondrion, most electrons follow which pathway?
a. Citric acid cycle  NADH  electron transport chain  oxygen
18. Brown fat cells produce a protein called thermogenin in their mitochondrial inner membrane.
Thermogenin is a channel that allows protons to diffuse across the membrane. What will
occur in the brown fat cells when they produce large amounts of thermogenin?
a. ATP synthesis will decrease, and heat generation will increase
19. One primary function of both alcohol fermentation and lactic acid fermentation is to
a. Oxidize NADH to NAD+
20. Why are carbohydrates and fats considered high-energy foods?
a. They have a large number of electrons associated with hydrogen
Test 1:
1. Which of the following membrane activities requires energy from ATP hydrolysis?
a. Movement of sodium ions from a lower concentration in a mammalian cell to a
higher concentration in the extracellular fluid.
2. Which of the following correctly describes the relationship between an enzyme and its
function?
a. Phosphatase: removal of a phosphate group
3. Which of the following enzymes adds a phosphate group to target proteins?
a. Kinase
4. The primary function of phosphatases in signal transduction is to
a. Inactivate protein kinases to turn off signal transduction.
5. Following activation of a receptor, which sequence below represents the correct order in
which components will be involved in a signaling pathway that utilizes the second
messenger cAMP?
a. G protein  adenyl cyclase  cAMP
6. The primary function of G proteins in signal transduction is
a. Transducing the signal from an activated receptor to the next protein in the
pathway
7. Phosphorylation cascades involving a series of protein kinases are useful for cellular
signal transduction because
a. They amplify the original signal manifold.
8. Lipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells
but affect only target cells because
a. Specific receptors are present only in target cells
9. The quickest way for a cell to stop a response to a signaling molecule or hormone is to
a. Remove phosphate groups from proteins involved in that pathway’s
phosphorylation cascade
10.
Five dialysis bags, constructed from a semipermeable membrane that is impermeable to
sucrose, were filled with various concentrations of sucrose and then placed in separate
beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute
intervals, the bags were massed (weighed) and the percent change in mass of each bag
was graphed.
Which line(s) in the figure represent bags that contain a solution with a lower sucrose
concentration than the initial beaker concentration of .6 M at the beginning of the
experiment?
a. D and E
b. Water will flow out to lower the concentration of the .6 outside and make it .3
11.
Which temperature and pH profile curves on the graphs were most likely generated from
analysis of an enzyme from a human stomach where conditions are strongly acid?
a. Curves 1 and 4
b. Low pH and temperature around 37 degrees Celsius
12. If an enzyme in solution is saturated with substrate, the most effective way to obtain a
faster yield of products is to
a. Add more of the enzyme.
13. Metabolic pathways that release stored energy by breaking down complex molecules are
known as
a. Catabolic pathways
14. Which of the following is true for anabolic pathways?
a. They consume energy to build polymers from monomers
15. The complete reactions of cellular respiration in the presence of oxygen result in which of
the following?
a. Oxidation of C6H12O6 and reduction of O2
16. In an oxidation-reduction reaction, the molecule that is oxidized
a. Loses electrons and loses potential energy.
17. The oxygen consumed during cellular respiration is involved directly in which process or
event?
a. Accepting electrons at the end of the electron transport chain
18. During glycolysis, when each molecule of glucose is catabolized to two molecules of
pyruvate, MOST of the potential energy contained in glucose is
a. Retained in the two pyruvates
19. Inside an active mitochondrion, most electrons follow which pathway?
a. Citric acid cycle  NADH  electron transport chain  oxygen
20. Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present
or absent?
a. Glycolysis
21. In addition to ATP, what are the end products of glycolysis?
a. NADH and pyruvate
22. Carbon dioxide (CO2) is released during which of the following stages of cellular
respiration?
a. Oxidation of pyruvate to acetyl coA and the citric acid cycle
23. The source of energy stored in glucose and used to synthesize ATP ultimately originates
from:
a. The sun
24. One primary function of both alcohol fermentation and lactic acid fermentation is to
convert NADH to NAD+ so that ____________ could continue in the absence of oxygen.
a. Glycolysis
25. Absorption of a photon of light by a chlorophyll molecule immediately
a. Boosts and electron to a higher energy state
26. If plants are grown with H2O containing heavy oxygen, subsequent analysis will show
that it first appears in which of the following molecules produced?
a. O2
27. Which o fteh following are products of the light reactions of photosynthesis that are
utilized in the Calvin cycle?
a. ATP and NADPH
28. Which of the following events occurs in the light reactions of photosynthesis?
a. Light is absorbed and funneled to reaction-center chlorophyll a
29. In a plant cell, where are ATP synthase complexes located?
a. Thylakoid membrane and inner mitochondrial membranes
30. What is the primary function of the Calvin cycle?
a. Produce simple sugars from carbon dioxide
31. Which of the following statements bets represents the relationship between the light
reactions and the Calvin cycle?
a. The light reactions provide ATP and NADPH to the Calvin cycle, and the Calvin
cycle returns ADP, Pi, and NADP+ to the light reactions
32. A gardener is concerned that her greenhouse is getting too hot from too much light, and
seeks to shade her plants with colored translucent plastic sheets. What color should she
use to reduce overall light energy, but still maximize plant growth?
a. Blue (100% absorbtion and small wavelength)
33. Which of the following sequences correctly represents the flow of electrons during
photosynthesis?
a. H2O  NADPH  Calvin cycle
34. Generation of proton gradients across membranes occurs during
a. Both photosynthesis and cellular respiration
35. Which of the following directly contribute to generation of the proton gradient in
photosynthesis?
a. Pumping protons using energy from electron transport AND splitting of water
36. A flask containing chloroplasts is places under a light which is set to cycle between 12
hours of light and 12 hours of dark. Production of oxygen is monitored. Which of the
following is most likely to be observed?
a. Oxygen production will be higher during the light cycle.
37. The pH of the inner thylakoid space has been measured, as have the pH of the stroma and
of the cytosol of a particular plant cell. Which, if any, relationship would you expect to
find?
a. The pH within the thylakoid is lower than that of the stroma.
38. Which of the following correctly depicts the flow of molecules between the
mitochondrioa and chloroplasts?
a. CO2 and water from mitochondria to chloroplasts; sugar and O2 from
chloroplasts to mitochondria.
39. The final electron acceptors are ______ for cellular respiration and ______ for the light
reactions of photosynthesis.
a. Oxygen; NADP+
40. ATP synthesis is most directly powered by
a. A proton gradient in chloroplasts and mitochondria.
Mitosis and Meiosis Quiz 4:
1. What is produced if a cell completes mitosis but does not undergo cytokinesis?
a. One cell with 2 nuclei, each identical to the nucleus of the parent cell
2. Humans produce skin cells by mitosis and gametes by meiosis. The nuclei of skin cells
produced by mitosis will have
a. Twice as much DNA as the nuclei of gametes produced by meiosis
3. Movement of chromosomes during anaphase would be most affected by a drug that
prevents
a. Prevents shortening of microtubules
4. A group of cells is assayed/tested for DNA content immediately before beginning mitosis
and is found to have an average of 16 picograms of DNA per nucleus. How many
picograms would be in a cell nucleus following completion of mitosis and cytokinesis?
a. 8
5. What is a cleavage furrow?
a. A groove in the plasma membrane between daughter nuclei
6. You have the technology necessary to measure each of the following in a sample of
animal cells: chlorophylls, organelle density, picograms of DNA, cell wall components,
and enzymatic activity. Which would you expect to increase significantly during the gap
phases (G1 and G2) of interphase?
a. Organelle density and enzymatic activity
Picture for 7 and 8 shows 2 pairs of homologous chromosomes (diploid, 4 unreplicated
chromosomes)
7. Which image displays the chromosomal composition of one daughter nucleus at
telophase of mitosis?
a. It’s the one that shows the same 4 unreplicated chromosomes (because they
already split)
8. What is the correct condition for a nucleus at prophase of mitosis?
a. It’s the one that shows the 4 replicated chromosomes (4 pairs of sister chromatids
still connected by the centromere)
9. Nucleotides can be radiolabeled before they are incorporated into newly forming DNA
and can therefore be assayed to track their incorporation. In a set of experiments, a
student—faculty research team used labeled T nucleotides and introduced these into the
culture of dividing human cells at specific times. The research team used the setup to
study the incorporation of labeled nucleotides into a culture of lymphocytes and found
that the lymphocytes incorporated the labeled nucleotide at a significantly higher level
after a pathogen was introduced into the culture. They concluded that
a. Infection causes lymphocytes to divide more rapidly.
b. This setup could also answer the question “What is the length of the S phase of
the cell cycle”
10. Which of the following is true of a species that has a chromosome number of 2n = 16?
a. Each cell has eight homologous pairs.
11. In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these
pairs, such as pair 14, which of the following do the two chromosomes of the pair have in
common?
a. Length, centromere position, and alleles
12. Which of the following happens during meiosis I?
a. Homologous chromosomes of a pair are separated from each other.
13. The following question refers to the essential steps in meiosis described below.
1. Formation of four new nuclei, each with half the chromosomes present in the parental
nucleus
2. Alignment of tetrads at the metaphase plate
3. Separation of sister chromatids
4. Separation of the homologs; no uncoupling of the centromere
5. Synapsis; chromosomes moving to the middle of the cell in pairs
Which steps take(s) place in both mitosis and meiosis?
a. 3
14. Independent assortment of chromosomes is a result of
a. the random and independent way in which each pair of homologous chromosomes
lines up at the metaphase plate during meiosis I.
15. During which phase(s) of meiosis does independent assortment occur
a. Meiosis 1. During metaphase I, This random distribution of homologous
chromosomes during meiosis is independent assortment, enabling lots of variation
16. When homologous chromosomes crossover, what occurs?
a. Specific proteins break the two strands and re-join them with their homologs.
17.
Refer to the life cycles illustrated in the figure to answer the following question: Which
of the life cycles is typical for animals?
a. I only
18. Refer to the life cycles illustrated in the figure to answer the following question: Which
of the life cycles is typical for plants and some algae?
a. III only
19.
Refer to the drawings in the figure of a single pair of homologous chromosomes as they
might appear during various stages of either mitosis or meiosis, and answer the following
questions.
Which diagram represents anaphase I of meiosis?
a. I
20. How is natural selection related to sexual reproduction as opposed to asexual
reproduction?
a. Sexual reproduction results in many new gene combinations, some of which will
lead to differential reproduction.
Test 2:
1. Taxol is an anticancer drug extracted from the Pacific yew tree that binds to microtubules
and prevents their depolymerization (breaking down of polymers). Actively dividing cells
treated with Taxol becomes blocked in which phase of mitosis?
a. Telophase
2. Measurements of the amount of DNA per nucleus were taken on a large number of cells
from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per
nucleus. In the beginning of which stage of the cell cycle would the nucleus contain 6
picograms of DNA?
a. G2
3.
4.
5.
6.
7.
8.
The lettered circle in Figure 12.1 shows a diploid nucleus with four chromosomes. There
are two pairs of homologous chromosomes, one long and the other short. One haploid set
is symbolized as black and the other haploid set is gray. The chromosomes in the
unlettered circle have not yet replicated. Choose the correct chromosomal conditions for
the following stages. What is the correct chromosomal condition for a nucleus at the
beginning of interphase?
a. E
What is the correct condition for a nucleus at prophase of mitosis?
a. B
How do cells that just completed meiosis compare with cells that have replicated their
DNA and are just about to begin meiosis?
a. They have half the number of chromosomes and ¼ the amount of DNA
Crossing over occurs during
a. Prophase I only
Centromeres of sister chromatids disjoin and chromatids separate.
a. Anaphase II only
Drawings of a single pair of homologous chromosomes as they might appear during
various stages of either mitosis and meiosis. Which diagram(s) represent(s) anaphase II
of meiosis?
a. V only
9. What was the most significant conclusion that Gregor Mendel drew from his experiments
with pea plants?
a. Traits are inherited in discrete units, and are not the results of the “blending” of
traits
10. When crossing an organism that homozygous recessive for a single trait with a
heterozygote, what is the chance of producing an offspring with the homozygous
recessive phenotype? Rr x rr
a. 50% rr
11. Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long
tails (t). What fraction of the progeny of crosses BbTt x BBtt will be expected to have
black fur and long tails (BB or Bb and tt)
a. ½
12. In certain plants, the tall trait is dominant to the short trait. If a heterozygous plant is
crossed with a homozygous tall plant, what is the probability that the offspring will be
short?
a. 0
13.
The following questions refer to the pedigree chart in Figure 14.2 for a family, some of
whose members exhibit the dominant trait, W. Affected individuals are indicated by a
dark square or circle.
What is the genotype of individual II-5?
a. ww
14. What is the probability that individual III-1 is Ww?
a. 1
15. Duchenne muscular dystrophy is an X-linked recessive disorder that is characterized by
severe muscle wasting and shorted life-span. Neither Tim nor Rhoda has the disorder, but
their firstborn son does have it. What is the probability that a second child of this couple
will have the disease?
a. 25% (but 50% of sons)
16. Which of the following statements correctly describes linkage?
a. The closer two genes are on a chromosome, the lower the probability that a
crossover will occur between them.
17.
Figure 12.1 shows a map of four genes on a chromosome.
Between which two genes would you expect the highest frequency of recombination?
a. A and G
18. It became apparent to Watson and Crick after completion of their model that the DNA
molecule could carry a vast amount of hereditary information based on which of the
following characteristics?
a. The sequence of bases
19. The original parent strand of a DNA segment is 5’ A-G-A-G-C-T 3’. Which is the correct
complementary strand of the segment?
a. 3’ T-C-T-C-G-A 5’
20. Cytosine (C) makes up 20% of the nucleotides in a sample of DNA from an organism.
Approximately what percentage of the nucleotides in this sample will be thymine (T).
a. 30%
Free Response:
1. Given a purple-flowered pea plant, we cannot tell if it is homozygous (PP) or
heterozygous (Pp) because both genotypes result in the same purple phenotype. Explain
how we could determine its genotype by crossing it with another pea plant and predict the
possible outcomes.
a. By crossing that given pea plant with a white-flowered pea plant (homozygous
recessive pp), the genotype of the unknown parent can be determined by the
phenotypes of the offspring. If there is any white, the parent must be
heterozygous. For a homozygous dominant parent (PP), the possible outcomes are
all purple (heterozygous Pp). For a heterozygous parent (Pp), the possible
outcomes are predicted to be 50% purple heterozygous (Pp) and 50% white
homozygous recessive (pp).
2. Identify and describe two mechanisms in meiosis that contribute to the genetic variation
arising from sexual reproduction.
a. Two mechanisms are independent assortment and crossing over. Homologous
chromosomes line up at the metaphase 1 plate, completely independent of other
pairs. Variations in orientation/organization of these chromosomes accounts for
genetic variation in sexual reproduction. In crossing over, part of one nonsister
chromatid separates and switches places (crosses over) with another nonsister
chromatid. Resulting in genetically different daughter cells from the parent cell.
3. Explain the similarities and differences between mitosis and meiosis for the properties
below. Be sure to include specific stages where applicable.
 Number of divisions
o In mitosis, 1 division occurs during anaphase.
o In meiosis, 2 divisions occur, once during anaphase 1 and again during
anaphase 2.
 Pairing of homologous chromosomes
o In mitosis, chromosomes are already duplicated in Interphase (S phase).
Homologous chromosomes pair during prophase.
o In meiosis, homologous chromosomes separate according to the law of
segregation during anaphase I. During prophase I, the chromosomes pair
up.
 Crossing over
o Crossing over is a process unique to meiosis, occurring during meiosis 1
(prophase 1 only).

Separation of sister chromatids
o In mitosis, the sister chromatids separate during anaphase.
o In meiosis, the sister chromatids cannot separate until anaphase II.
 Number of daughter cells and relative genetic composition
o In mitosis, 1 parent cell splits into 2 daughter cells genetically identical to
the parent (clone).
o In meiosis, 1 parent (diploid) splits into 4 haploid daughter cells with
genetic variation different from the parent cell.
4. In certain a certain species of plant, the diploid number of chromosomes is 4 (2n=4).
Flower color is controlled by a single gene in which the green allele (G) is dominant to
the purple allele (g). Plant height is controlled by a different gene in which the dwarf
allele (D) is dominant to the tall allele (d). Individuals of the parental (P) generation with
the genotypes GGDD and ggdd were crossed to produce F1 progeny.
a. Identify the possible genotypes and phenotypes of the F1 progeny.
i. All of the F1 progeny will have the genotype GgDd and the phenotype
green color and dwarf height.
b. Identify the possible phenotypes and their ratios in the offspring of a testcross
between an F1 individual and a ggdd individual.
i. There are 4 possible phenotypes. The possible phenotypes include green
and dwarf, green and tall, purple and dwarf, and purple and tall. The
possible genotypes include GgDd, Ggdd, ggDd, and ggdd. Each
genotype/phenotype would appear in a 1:1:1:1 ratio with each offspring
having a 25% chance of any of those genotypes.
Free Response Questions to look out for:
1. What are the major biological molecules and what functions do they serve?
 Carbohydrates, Lipids, Proteins, and Nucleic Acids
 Carbohydrates: provide fuel and build structures in the body; store energy.
 Lipids: fats (energy), phospholipids (lipid bilayer of membranes), and steroids
(cholesterol as part of membrane and hormones = signaling molecules)
 Proteins: structure, catalyze reactions, transport, receive in cell signaling
 Nucleic Acids: store, transmit, help express hereditary info (DNA and RNA)
2. How do enzymes work? What influences enzyme function?
 They speed up specific (specific due to shape of enzyme) reactions by providing
an alternative reaction pathway of lower activation energy. Only alter rate of
reaction and are not consumed by the reaction (remain unchanged).
 Many enzymes consist of a protein and a non-protein (called the cofactor). Bonds
that hold proteins in their secondary and tertiary structures are disrupted by
changes in temperature and pH. This affects shapes and so the catalytic activity of
an enzyme is pH and temperature sensitive.
3. What are the major functions of each organelle?
 Mitochondria = produces energy through cellular respiration
 ribosomes = create proteins
 rough endoplasmic reticulum = transport and storage
 smooth endoplasmic reticulum = creates lipids or fat
 chloroplast = creates glucose
 golgi apparatus = synthesis, packages and releases concentrate proteins or lipids
 cytoplasm = where all chemicals take place
 cytoskeleton = supports structure and helps move synthesized proteins
 lysosomes = contain hydrolytic enzymes for digestion
 vacuole = contains food or water, aid in digestion
 cell membrane = separates cell contents from the environment
 nucleus = information center of the cell
4. What are the differences between active and passive transport and how do membrane
proteins play a role in these processes?
ACTIVE
PASSIVE

Definition

Active Transport
uses ATP to pump
molecules
AGAINST/UP the
concentration
gradient. Transport
occurs from a low
concentration of
solute to high
concentration of
solute. Requires
cellular energy.

Movement of
molecules
DOWN the
concentration
gradient. It goes
from high to low
concentration, in
order to maintain
equilibrium in the
cells. Does not
require cellular
energy.

Types of
Transport

Endocytosis, cell
membrane/sodiumpotassium pump &
exocytosis

Diffusion,
facilitated
diffusion, and
osmosis.

Functions

Transports
molecules through
the cell membrane
against the
concentration
gradient so more of
the substance is
inside the cell (i.e.
a nutrient) or
outside the cell
(i.e. a waste) than
normal. Disrupts
equilibrium
established by
diffusion.

Maintains
dynamic
equilibrium of
water, gases,
nutrients, wastes,
etc. between cells
and extracellular
fluid; allows for
small nutrients
and gases to
enter/exit. No
NET
diffusion/osmosis
after equilibrium
is established.

Types of
Particles
Transported

proteins, ions,
large cells,
complex sugars.

Anything soluble
(meaning able to
dissolve) in
lipids, small
monosaccharides,
water, oxygen,
carbon dioxide,
sex hormones,
etc.

Examples

phagocytosis,
pinocytosis,
sodium/potassium
pump, secretion of
a substance into
the bloodstream
(process is
opposite of
phagocytosis &
pinocytosis)

diffusion,
osmosis, and
facilitated
diffusion.

Importance

In eukaryotic cells,
amino acids,
sugars and lipids
need to enter the
cell by protein
pumps, which
require active
transport. These
items either cannot
diffuse or diffuse
too slowly for
survival.

It maintains
equilibrium in the
cell. Wastes
(carbon dioxide,
water, etc.)
diffuse out and
are excreted;
nutrients and
oxygen diffuse in
to be used by the
cell.
5. What are the stages of cell signaling? How do phosphorylation cascades and G-protein
signaling work?
 Reception – where the target cell detects a signalling molecule present in the
exogenous environment.
 Transduction – the conversion of the signal to a form that can bring about a
specific cellular response.
 Response – the specific cellular effect brought about by the signalling molecule.
 Phosphorylation reactions often occur in series, or cascades, in which one kinase
activates the next. These cascades serve to amplify the original signal, but also
improving the signal (less noise) and allowing for cross talk between different
pathways. To turn of the signal, the proteins will be dephosphorylated, where
phosphatase removes a phosphate group from a protein
 How G Proteins Work: The first step in this complex signaling system involves
the binding of specific ligands. G protein  adenylyl cyclase  cAMP
6. How are cellular respiration and photosynthesis connected?
 They are complementary processes, and also opposites of each other. During
photosynthesis, the plant needs carbon dioxide and water-- both of which are
released into the air during respiration. And during respiration, the plant needs
oxygen and glucose, which are both produced through photosynthesis! So in a
way, the products of photosynthesis support respiration, and the products of
respiration support photosynthesis, forming a cycle.
NOTES for CELLULAR RESPIRATION:
Summary:
Glucose  glycolysis  pyruvate oxidation (link/transition reaction)  Krebs/Citric Acid
Cycle  Electron Transport chain
Glycolysis:
 WHERE: cytosol
 REACTANTS: C6H12O6, 2 NAD+, 2 ATP, 4 ADP, 4 Pi
 PRODUCTS: 2 pyruvates, 2 NADH, 4 ATP (net 2 ATP), 2 H2O
 C6H12O6 is oxidized, NAD+ is reduced to NADH
 NAD+ is a co-enzyme necessary for the reaction to go forward, H+ donator in the electron
transport chain
 Cellular respiration is catabolic: breaks the small molecules from digestion into even
smaller ones as ATP is created (ATP needed for movement, body heat, etc)
Pyruvate Oxidation:
 WHERE: mitochondrial inner membrane
 REACTANTS: 2 pyruvates, 2 co-enzyme A (CoA), 2 NAD+
 PRODUCTS: 2 acetyl CoA, 2 NADH + H+, 2 CO2
 Acetyl CoA function: main function is to deliver the acetyl group to the citric acid cycle
(Krebs cycle) to be oxidized for energy production
 2 CO2 released
Citric Acid Cycle:
 WHERE: mitochondrial inner membrane
 REACTANTS: 2 acetyl CoA, 2 ADP, 2 Pi, 6 NAD+, 2 FAD
 PRODUCTS: 2 ATP, 6 NADH, 2 FADH2, 4 CO2
 For every acetyl-CoA that enters the Krebs cycle, the cycle turns once. For every glucose
molecule that starts cell respiration, 2 pyruvates are formed, forming 2 acetyl CoAs, thus
turning the Krebs cycle twice
 FAD is a co-enzyme necessary for the reaction as well as an electron donor in the
electron transport chain
 During Krebs cycle both NAD+ & FAD are reduced to NADH & FADH2 respectively
 4 CO2 released
Electron Transport Chain:
 WHERE: mitochondrial inner membrane
 REACTANTS: 10 NADH, 2 FADH2, 6 O2, ADP + Pi



PRODUCTS: 36 – 38 ATPs, 4 H2O
Electrons enter ETS from NADH & FADH2
As the electrons are passed from carrier to carrier, H+ are pumped from the inner
membrane into the intermembrane space, creating a huge concentration gradient for the
H+ to flow down
o The H+ flow back into the inner membrane through ATP synthase, thus creating
ATP from ADP & Pi
o The electrons “jump off” the last carrier & combine with O2 to form H2O
 This process of producing ATP in the presence of O2 is called oxidative phosphorylation
& the overall process of utilizing a concentration gradient to produce ATP is called
chemiosmosis
 All other energy released as heat
Fermentation:
 Ability to produce ATP when oxygen is NOT available
 2 Phases: Glycolysis and reduction of pyruvate to lactic acid or alcohol
 1. Pyruvate is reduced to lactic acid or alcohol via the oxidation of NADH back to NAD+
 2. Once NAD + is regenerated it can go back to the glycolytic pathway & be reduced
again, thus enabling glycolysis to keep on running
 Only produces 2 ATP per glucose
________________________________________________________________________
7. What are the major phases of the cell cycle?

8. How are Mendel’s discoveries and meiosis related?
The Law of Dominance
A dominant trait is a trait whose appearance will always be seen in offspring. In other
words, dominance describes the relationship between two alleles. If an individual inherits
two different alleles from each of its two parents and the phenotype of only one allele is
visible in the offspring, then that allele is said to be dominant. Mendel's law of
dominance states that if one parent has two copies of allele A -- the dominant allele -- and
the second parent has two copies of allele a-- the recessive allele -- then the offspring will
inherit an Aa genotype and display the dominant phenotype.
The Law of Segregation
A parent may have two distinct alleles for a certain gene, each on one copy of a given
chromosome. Mendel's second law, the law of segregation, states that these two alleles
will be separated from each other during meiosis. Specifically, in the second of the two
cell divisions of meiosis the two copies of each chromosome will be separated from each
other, causing the two distinct alleles located on those chromosomes to segregate from
one another.
The Law of Independent Assortment
Mendel's third law, the law of independent assortment, states that the way an allele pair
gets segregated into two daughter cells during the second division of meiosis has no
effect on how any other allele pair gets segregated. In other words, the traits inherited
through one gene will be inherited independently of the traits inherited through another
gene because the genes reside on different chromosomes that are independently assorted
into daughter cells during meiosis.
9. What are sex-linked genes?
 If a gene is found only on the X chromosome and not the Y chromosome, it is
said to be a sex-linked trait. Because the gene controlling the trait is located on
the sex chromosome, sex linkage is linked to the gender of the individual.
 Usually found on the X chromosome because it is so much larger than the Y
chromosome.
10. What are linked genes? How does the linkage of genes affect phenotypic ratios?
 When two genes are located on the same chromosome they are called linked
genes because they tend to be inherited together. They are an exception to
Mendel's law of Segregation because these genes are not inherited independently
 Since certain traits travel together, normal Mendelian predictions of phenotypes
are off, with some traits being more likely to occur together than others (like red
hair and freckles).
11. What are the major features of DNA molecules? How does its structure allow storage
and replication of hereditary information?
 DNA is double-stranded, so there are two polynucleotide stands alongside each
other. The two strands are wound round each other to form a double helix. The
two strands are joined together by hydrogen bonds between the bases. The bases
therefore form base pairs, which are like rungs of a ladder. The base pairs are
specific. A only binds to T (and T with A), and C only binds to G (and G with C).
These are called complementary base pairs. This means that whatever the
sequence of bases along one strand, the sequence of bases on the other strand
must be complementary to it. (Incidentally, complementary, which means
matching, is different from complimentary, which means being nice.)




It is simply the order, or "sequence" of the four bases along the DNA spine that
provides the instructions for making the substances of the human body. The four
bases are referred to by the letters A, T, C and G, and their order literally "spells"
out the genetic "code". The variable sequence of bases from individual to
individual is one source of biological variation.
Before a cell divides, its nucleus must divide. But before that happens, the
chromosomes must have become double. So the first stage is that DNA which the
chromosomes contain must replicate, i.e. become double, by making copies of
itself. The 2 strands of the DNA double helix can separate, under the influence of
special enzymes in the nucleus, but each half remains attached along its length,
like the 2 sections of a zip, because the sides of the strands are strongly joined.
Each strand then acts as a basis for rebuilding the missing other strand from which
it has been separated. It is said that each strand forms a template on which it
reforms its complementary strand. Enzymes within the nucleus match the
appropriate base
1 double strand becomes 2 identical double strands