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WorksheetsAP Biology Exam Review
Total questions: 158
Worksheet time: 1hrs 19mins
In eukaryotic cells, chromosomes are composed of DNA
and phospholipids
only
and proteins
and RNA
A flask containing photosynthetic green algae and a control flask containing water with no algae are both placed under a bank of lights, which are set to cycle between 12 hours of light and 12 hours of dark. The dissolved oxygen concentrations in both flasks are monitored. Predict what the relative dissolved oxygen concentrations will be in the flask with algae compared to the control flask.
the dissolved oxygen in the flask with algae will always be higher
the dissolved oxygen in the flask with algae will always be lower
the dissolved oxygen in the flask with algae will be higher in the light, but the same in the dark
the dissolved oxygen in the flask with algae will be higher in the light, but lower in the dark
in photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during...
photosynthesis only
respiration only
both photosynthesis and respiration
neither photosynthesis nor respiration
Which of the following represents the difference between the free-energy content of the reactants and the free-energy content of the products in Figure 6.4?
b
d
c
e
a
Which of the following represents the activation energy required for a noncatalyzed reaction in Figure 6.4?
c
e
a
b
d
Which of the following terms best describes the forward reaction in Figure 6.4?
chemical equilibrium, G=0
exergonic, G<0
exergonic, G>0
endergonic, G<0
endergonic, G>0
Which of the following represents the activation energy required for the enzyme-catalyzed reaction in Figure 6.4?
d
e
a
c
b
Which of the following represents the ΔG of the reaction in Figure 6.4?
d
e
c
b
a
A beaker contains 100 mL of NaOH solution at pH = 13. A technician carefully pours into the beaker 10 mL of HCl at pH = 1. Which of the following statements correctly describes the results of this mixing?
the concentration of Cl- ion will be 0.1 M
the pH of the beaker's contents will be neutral
the concentration of Na+ ion will rise
the pH of the beaker's contents will decrease
What compound provides the reducing power for the Calvin cycle reactions?
ATP
NAD+
NADH
NADPH
In the thylakoid membranes, what is the main role of the pigment molecules in a light-harvesting complex?
split water and release oxygen to the reaction-center chlorophyll
transfer light energy to the reaction-center chlorophyll
synthesize ATP from ADP and Pi
transfer electrons to ferredoxin and then NADPH
What is the difference between covalent bonds and ionic bonds?
Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between atoms
Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms
Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms
Covalent bonds involve the transfer of electrons between atoms; ionic bonds involve the sharing of electrons between atoms
The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?
C3O6H3
C18H36O18
C6H10O5
C18H32O16
Buffers are substances that help resist shifts in pH by..
both donating H+ to a solution when bases are added and accepting H+ when acids are added
releasing H+ to a solution when acids are added
releasing OH- to a solution when bases are added
donating H+ to a solution when bases are added
The tertiary structure of a protein is the...
bonding together of several polypeptide chains by weak bonds
order in which amino acids are joined in a polypeptide chain
unique three-dimensional shape of the fully folded polypeptide
organization of a polypeptide chain into an α helix or β pleated sheet
G1 is represented by which numbered part(s) of the cycle?
I or V
V only
III only
IV only
MPF reaches its threshold concentration at the end of this stage.
V
IV
I
III
Which number represents DNA synthesis?
IV
II
I
V
Which number represents the point in the cell cycle during which the chromosomes are replicated?
IV
V
II
III
In Figure 9.3, mitosis is represented by which numbered part(s) of the cycle?
IV
V
II
III
At which of the numbered regions would you expect to find cells at metaphase?
I
II
III
IV
Mammalian blood contains the equivalent of 0.15 M NaCl. Seawater contains the equivalent of 0.45 M NaCl. What will happen if red blood cells are transferred to seawater?
NaCl will be exported from the red blood cells by facilitated diffusion
The blood cells will take up water, swell, and eventually burst
Water will leave the cells, causing them to shrivel and collapse
NaCl will passively diffuse into the red blood cells
CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they..
fix CO2 into organic acids during the night
fix CO2 into sugars in the bundle-sheath cells
fix CO2 into pyruvate in the mesophyll cells
use the enzyme phosphofructokinase, which outcompetes rubisco for CO2
If you examine side A after three days, you should find...
a decrease in the concentration of NaCl and glucose and an increase in the water level
a decrease in the concentration of NaCl, an increase in water level, and no change in the concentration of glucose
no net change in the system
a decrease in the concentration of NaCl and a decrease in the water level
At the beginning of the experiment, side A...
is hypertonic to side B
is hypotonic to side B
is isotonic to side B
is hypertonic to side B with respect to glucose
Which of the following triggers the cell's passage past the G2 checkpoint into mitosis?
protein kinase
cyclin
cdk
MPF
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
CO2 and glucose
H2O and O2
ADP, Pi, and NADP+
ATP and NADPH
Which metabolic pathway is common to both cellular respiration and fermentation?
the oxidation of pyruvate to acetyl CoA
the citric acid cycle
oxidative phosphorylation
glycolysis
When oxygen is released as a result of photosynthesis, it is a direct by-product of...
reducing NADP+
splitting water molecules
chemisosmosis
the electron transfer system of photosystem I
If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?
10
20
40
80
In alcohol fermentation, NAD+ is regenerated from NADH by...
reduction of acetaldehyde to ethanol (ethyl alcohol)
oxidation of pyruvate to acetyl CoA
reduction of pyruvate to form lactate
oxidation of ethanol to acetyl CoA
If cells are grown in a medium containing radioactive 35S, which of these molecules will be labeled?
phospholipids
nucleic acids
proteins
both proteins and nucleic acids
Which of the following is true for anabolic pathways?
They do not depend on enzymes
They are usually highly spontaneous chemical reactions
They consume energy to build up polymers from monomers
They release energy as they degrade polymers to monomers
The movement of water across biological membranes can best be predicted by...
prevailing weather conditions
level of active transport
water potentials
aquaporins
The element present in all organic molecules is...
hydrogen
oxygen
carbon
nitrogen
Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?
water's change in density when it condenses
the absorption of heat by the breaking of hydrogen bonds
water's ability to dissolve molecules in the air
the release of heat by the formation of hydrogen bonds
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the...
oxidation of glucose and other organic compounds
flow of electrons down the electron transport chain
affinity of oxygen for electrons
H+ movement down its concentration gradient
Based on the figure given below, which of these experimental treatments would increase the rate of sucrose transport into the cell?
decreasing extracellular sucrose concentration
decreasing extracellular pH
decreasing cytoplasmic pH
adding an inhibitor that blocks regeneration of ATP
In the cells of some organisms, mitosis occurs without cytokinesis. This will result in...
cells with more than one nucleus
cells that are unusually small
cells lacking nuclei
destruction of chromosomes
Which of the following does not occur during mitosis?
condensation of the chromosomes
replication of the DNA
separation of sister chromatids
spindle formation
When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?
the pH of the matrix increases
ATP synthase pumps protons by active transport
the electrons gain free energy
the cytochromes phosphorylate ADP to form ATP
Which of the following is present in a prokaryotic cell?
chloroplast
ribosome
mitochondrion
nuclear envelope
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is...
oxygen
water
NAD+
pyruvate
Which of the following is the best description of a control for an experiment?
the control group is kept in an unchanging environment
the control is left alone by the experimenters
only the experimental group is tested or measured
the control group is exposed to only one variable rather than several
According to the induced fit hypothesis of enzyme catalysis, which of the following is correct?
the binding of the substrate depends on the shape of the active site
The active site creates a microenvironment ideal for the reaction
Some enzymes change their structure when activators bind to the enzyme
The binding of the substrate changes the shape of the enzyme's active site
A carbon atom is most likely to form which of the following bonds with other atoms?
ionic bond
hydrogen bond
covalent bond
covalent bonds and hydrogen bonds
Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?
catabolism
catalysis
metabolism
dehydration
A chemical reaction that has a positive ΔG is best described as...
spontaneous
entropic
exergonic
endergonic
Which of the following normally occurs regardless of whether or not oxygen (O2) is present?
glycolysis
fermentation
oxidation of pyruvate to acetyl coA
citric acid cycle
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 which stage of the cell cycle did the nucleus contain 6 picograms of DNA?
M
S
G1
G2
Which type of bond must be broken for water to vaporize?
both hydrogen bonds and ionic bonds
both polar covalent bonds and hydrogen bonds
polar covalent bonds
hydrogen bonds
The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation in eukaryotic cells is...
oxidation of glucose to CO2 and water
the thermodynamically favorable flow of electrons from NADH to the mitochondrial electron transport carriers
the final transfer of electrons to oxygen
the proton-motive force across the inner mitochondrial membrane
Which line in the graph represents the bag that contained a solution isotonic to the 0.6 M solution at the beginning of the experiment?
A
B
C
D
E
Which line or lines in the graph represent(s) bags that contain a solution that is hypertonic at 50 minutes?
A and B
C
D
B
Which line in the graph represents the bag with the highest initial concentration of sucrose?
A
B
C
D
E
Which component is the peripheral protein?
A
B
C
D
E
Which component is cholesterol?
A
B
C
D
E
Which component is the fiber of the extracellular matrix?
A
B
C
D
E
Which component is a microfilament of the cytoskeleton?
A
B
C
D
E
Which component is a glycolipid?
A
B
C
D
E
An open beaker of pure water has a water potential (Ψ) of...
+0.07 MPa
-0.23 MPa
0.0 (zero)
+0.23 MPa
The reactions that produce molecular oxygen (O2) take place in...
the light reactions alone
the Calvin cycle alone
both the light reactions and the Calvin cycle
neither the light reactions nor the Calvin cycle
Density-dependent inhibition is explained by which of the following?
As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to produce control factors
As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing
As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor
As cells become more numerous, more and more of them enter the S phase of the cell cycle
Amino acids are acids because they always possess which functional group?
amino
carboxyl
carbonyl
hyrdoxyl
At which phase are centrioles beginning to move apart in animal cells?
telophase
anaphase
metaphase
prophase
After the system reaches equilibrium, what changes are observed?
the water level is higher in side A than side B
the water level is higher in side B than side A
the water level is unchanged
the molarity of sucrose is higher than that of glucose on side A
Initially, in terms of tonicity, the solution in side A with respect to that in side B is...
hypotonic
plasmolyzed
isotonic
hypertonic
Which of the following are directly associated with photosystem I?
harvesting of light energy by ATP
receiving electrons from the thylakoid membrane electron transport chain
generation of molecular oxygen
extraction of hydrogen ions from the splitting of water
Two atoms appear to have the same mass number. These atoms...
must have the same atomic number, the same number of protons + neutrons, the same number of electrons, and the same chemical properties
must have the same number of protons + neutrons
must have the same atomic number
must have the same chemical properties
The MPF protein complex turns itself off by...
activating an enzyme that stimulates cyclin
activating the anaphase-promoting complex
exiting the cell
activating a process that destroys cyclin components
Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
It produces much less ATP than does oxidative phosphorylation
It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms
It is found in prokaryotic cells but not in eukaryotic cells
It relies on chemiosmosis, which is a metabolic mechanism present only in the first cells' prokaryotic cells
Which of the following is true regarding saturated fatty acids?
they are the principal molecules in lard and butter
they are usually produced by plants
they are usually liquid at room temperature
they have double bonds between the carbon atoms of the fatty acids
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?
curves 1 and 4
curves 3 and 4
curves 2 and 4
curves 1 and 5
Which curve(s) on the graphs may represent the temperature and pH profiles of an enzyme taken from a bacterium that lives in a mildly alkaline hot springs at temperatures of 70°C or higher?
curves 3 and 4
curves 1 and 5
curves 3 and 5
curves 2 and 5
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
competitive inhibition
denaturation of the enzyme
saturation of the enzyme activity
allosteric inihibition
What is a cleavage furrow?
a groove in the plasma membrane between daughter nuclei
the separation of divided prokaryotes
the metaphase plate where chromosomes attach to the spindle
the space that is created between two chromatids during anaphase
Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a pH 8 solution. What would be likely to happen?
The isolated chloroplasts will make ATP
The Calvin cycle will be activated
Cyclic photophosphorylation will occur
The isolated chloroplasts will generate oxygen gas
What is the correct chromosomal condition for one daughter nucleus at telophase of mitosis?
A
B
C
D
E
Where is ATP synthase located in the mitochondrion?
cytosol
electron transport chain
outer membrane
inner membrane
Which of the following is an example of potential rather than kinetic energy?
the muscle contractions of a person mowing grass
water rushing over Niagara falls
light flashes emitted by a firefly
a molecule of glucose
When a cell is in late anaphase of mitosis, which of the following will we see?
a clear area in the middle of the cell
chromosomes clustered at the poles
individual chromatids beginning to separate from one another
chromosomes clustered tightly at the center
The value for Ψ in root tissue was found to be -0.15 MPa. If you take the root tissue and place it in a 0.1 M solution of sucrose (Ψ = -0.23 MPa), the net water flow would...
be in both directions and the concentrations would remain equal
occur only as ATP was hyrdolyzed in the tissue
be impossible to determine from the values given here
be from the tissue into the sucrose solution
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, the color of which allows passage of only that wavelength. What color should she use to reduce overall light energy, but still maximize plant growth?
green
blue
yellow
orange
What wavelengths of light should be used to maximize plant growth with a minimum of energy expenditure?
full-spectrum white light
green light
a mixture of blue and red light
yellow light
Halobacterium has a photosynthetic membrane that appears purple. Its photosynthetic action spectrum is the inverse of the action spectrum for green plants. (That is, the Halobacterium action spectrum has a peak where the green plant action spectrum has a trough.) What wavelengths of light do the Halobacterium photosynthetic pigments absorb?
red and yellow
blue, green, and red
green and yellow
red and green
What wavelength of light in Figure 8.1 is most effective in driving photosynthesis?
420 mm
475 mm
575 mm
625 mm
Figure 8.1 shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?
green and yellow wavelengths inhibit the absorption of red and blue wavelengths
bright sunlight destroys photosynthetic pigments
oxygen given off during photosynthesi interferes with the absorption of light
other pigments absorb light in addition to chlorophyll a
How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?
by decreasing the activation energy of the reaction
by acting as a coenzyme for the reaction
by changing the shape of the enzyme's active site
by binding at the active site of the enzyme
All of the following contain amino acids except...
antibodies
insulin
cholesterol
enzymes
What did Engelmann conclude about the congregation of bacteria in the red and blue areas?
Bacteria released excess carbon dioxide in these areas
Bacteria congregated in these areas due to an increase in the temperature of the red and blue light
Bacteria congregated in these areas because these areas had the most oxygen being released
Bacteria are attracted to red and blue light and thus these wavelengths are more reactive than other wavelengths
If you ran the same experiment without passing light through a prism, what would you predict?
There would be no difference in results
The bacteria would be relatively evenly distributed along the algal filaments
The number of bacteria present would decrease due to an increase in the carbon dioxide concentration
The number of bacteria present would increase due to an increase in the carbon dioxide concentration
An outcome of this experiment was to help determine the relationship between...
heterotrophic and autotrophic organisms
wavelengths of light and the rate of aerobic respiration
wavelengths of light and the amount of heat released
wavelengths of light and the rate of photosynthesis
Even though plants carry on photosynthesis, plant cells still use their mitochondria for oxidation of pyruvate. When and where will this occur?
in photosynthetic cells in the light, while photosynthesis occurs concurrently
in nonphotosynthesizing cells only
in cells that are storing glucose only
in all cells all the time
Which of the following is a statement of the first law of thermodynamics?
energy cannot be created or destroyed
the entropy of the universe is decreasing
the entropy of the universe is constant
kinetic energy is stored energy that results from the specific arrangement of matter
During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is...
transferred to ADP, forming ATP
transferred directly to ATP
retained in the two pyruvates
stored in the NADH produced
Why is ATP an important molecule in metabolism?
Its terminal phosphate group contains a strong covalent bond that, when hydrolyzed, releases free energy
Its terminal phosphate bond has higher energy than the other two
It is one of the four building blocks for DNA synthesis
It provides energy coupling between exergonic and endergonic reactions
In Figure 6.2, why does the reaction rate plateau at higher reactant concentrations?
Feedback inhibition by product occurs at high reactant concentrations
Most enzyme molecules are occupied by substrate at high reactant concentrations
The reaction nears equilibrium at high reactant concentrations
The activation energy for the reaction increases with reactant concentration
For the enzyme-catalyzed reaction shown in Figure 6.2, which of these treatments will cause the greatest increase in the rate of the reaction, if the initial reactant concentration is 1.0 micromolar?
doubling the activation energy needed
cooling the reaction by 10°C
doubling the concentration of the reactants to 2.0 micromolar
doubling the enzyme concentration
A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are being absorbed by this pigment?
red and yellow
blue and violet
green and yellow
blue, green, and red
Which of the following is true for all exergonic reactions?
The products have more total energy than the reactants
the reaction proceeds with a net release of free energy
The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants.
A net input of energy from the surroundings is required for the reactions to proceed
In cellular respiration, the energy for most ATP synthesis is supplied by...
high-energy phosphate bonds in organic molecules
a proton gradient across a membrane
converting oxygen to ATP
transferring electrons from organic molecules to pyruvate
Cells from advanced malignant tumors often have very abnormal chromosomes as well as an abnormal number of chromosomes. What might explain the association between malignant tumors and chromosomal abnormalities?
transformation introduces new chromosomes into cells
cell cycle checkpoints are not in place to stop cells with chromosomal abnormalities
cancer cells are no longer anchorage dependent
cancer cells are no longer density dependent
What is the primary function of the Calvin cycle?
use ATP to release carbon dioxide
use NADPH to release carbon dioxide
split water and release oxygen
synthesize simple sugars from carbon dioxide
Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?
The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, i, and NADP+ to the light reactions
The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the cycle provides water and electrons to the light reactions
The light reactions supply the Calvin cycle with CO2 to produce sugars, and the Calvin cycle supplies the light reactions with sugars to produce ATP
The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle provides the light reactions with water to split
Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components. In animal cells, which of the following organelles contains these hydrolytic enzymes?
central vacuole
peroxisome
chloroplast
lysosome
Besides the ability of some cancer cells to overproliferate, what else could logically result in a tumor?
enhanced anchorage dependence
changes in the order of cell cycle stages
lack of appropriate cell death
inability to form spindles
Which of the following is not a monomer/polymer pairing?
monosaccharide/polysaccharide
amino acid/protein
triglyceride/phospholipid bilayer
deoxyribonucleotide/DNA
All cell cycle checkpoints are similar in which way?
they respond to the same cyclins
they utilize the same cdks
they give the go-ahead signal to progress to the next checkpoint
they each have only one cyclin/cdk complex
How might an amino acid change at a site distant from the active site of the enzyme alter the enzyme's substrate specificity?
by changing the enzyme's stability
an amino acid change away from the active site cannot alter the enzyme's substrate specificity
by changing the enzyme's pH optimum
by changing the shape of the protein
How many electron pairs does carbon share in order to complete its valence shell?
1
2
3
4
8
How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?
12
11
10
9
8
The NADPH required for the Calvin cycle comes from...
reactions initiated in photosystem 1
reactions initiated in photosystem 2
the citric acid cycle
glycolysis
Where are the molecules of the electron transport chain found in plant cells?
thylakoid membranes of chloroplasts
stroma of chloroplasts
outer membrane of mitochondria
matrix of mitochondria
Which of the following is true concerning cancer cells?
They do not exhibit density-dependent inhibition when growing in culture
When they stop dividing, they do so at random points in the cell cycle
They are not subject to cell cycle controls
When they stop dividing, they do so at random points in the cell cycle; they are not subject to cell cycle controls; and they do not exhibit density-dependent inhibition when growing in culture.
Which of the following statements regarding enzymes is true?
Enzymes make the rate of a reaction independent of substrate concentrations
Enzymes change the equilibrium point of the reactions they catalyze
Enzymes increase the rate of a reaction by lowering the activation energy barrier
Enzymes increase the rate of a reaction by reducing the rate of reverse reactions
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
electron transport
glycolysis
the citric acid cycle
oxidative phosphorylation
A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from..
nearly any eukaryotic organism
an animal, but not a plant
bacterium
any multicellular organism, such as a plant or an animal
In any ecosystem, terrestrial or aquatic, which of the following are always necessary?
autotrophs and heterotrophs
producers and primary consumers
photosynthesizers
autotrophs
What is the term for metabolic pathways that release stored energy by breaking down complex molecules?
anabolic pathways
catabolic pathways
fermentation pathways
thermodynamic pathways
Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called...
ATPases
kinetochores
kinases
cyclins
What is the structural feature that allows DNA to replicate?
disulfide bonding (bridging) of the two helixes
twisting of the molecule to form an α helix
three-component structure of the nucleotides
complementary pairing of the nitrogenous bases
During aerobic respiration, electrons travel downhill in which sequence?
food--->citric acid cycle--->ATP--->NAD+
food--->NADH--->electron transport chain--->oxygen
glucose--->pyruvate--->ATP--->oxygen
glucose--->ATP--->electron transport chain--->NADH
In a plant cell, where are the ATP synthase complexes located?
thylakoid membrane only
plasma membrane only
inner mitochondrial membrane only
thylakoid membrane and inner mitochondrial membrane
The oxygen consumed during cellular respiration is involved directly in what process or event?
glycolysis
accepting electrons at the end of the electron transport chain
the citric acid cycle
the oxidation of pyruvate to acetyl coA
A molecule with the formula C18H36O2 is probably a...
nucleic acid
carbohydrate
protein
fatty acid
If ΨP = 0.3 MPa and ΨS = -0.45 MPa, the resulting Ψ is...
-0.15 MPa
+0.15 MPa
-0.75 MPa
+0.75 MPa
According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids?
they have hydrophilic tails in the interior of the membrane
they are free to depart from the membrane and dissolve in the surrounding solution
they can move laterally along the plane of the membrane
thye occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane
Which of the following is a protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active?
PDGF
Cdk
protein kinase
cyclin
What maintains the secondary structure of a protein?
disulfide bonds
hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
hydrophobic interactions
hydrogen bonds between the R groups
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?
as a pentose
as a hexose
as a disaccharide
as a polysaccharide
All of the following are polysaccharides except...
lactose
glycogen
chitlin
cellulose
Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's...
free-energy content
entropy
equilibrium point
activation energy
Which two functional groups are always found in amino acids?
ketone and methyl
hydroxyl and carboxyl
carboxyl and amino
amino and sulfhydryl
Which of the following is not a polymer?
glucose
starch
cellulose
DNA
Where does the Calvin cycle take place?
stroma of the chloroplast
thylakoid membrane
cytoplasm surrounding the chloroplast
interior of the thylakoid (thylakoid space)
Where does glycolysis take place in eukaryotic cells?
mitochondrial matrix
mitochondrial inner membrane
mitochondrial outer membrane
cytosol
The active site of an enzyme is the region that...
is involved in the catalytic reaction of the enzyme
binds allosteric regulators of the enzyme
binds noncompetitive inhibitors of the enzyme
is inhibited by the presence of a coenzyme or a cofactor
A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. How many picograms would be found at the end of S and the end of G2?
8;8
8;16
16;8
16;16
In order for a protein to be an integral membrane protein it would have to be...
amphipathic, with at least one hydrophobic region
hydrophobic
completely covered with phospholipids
hydrophilic
Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells?
4
8
16
32
If there are 20 chromatids in a cell, how many centromeres are there?
10
20
40
80
What is produced if a cell divides by mitosis but does not undergo cytokinesis?
two cells, one cell containing two nuclei and a second cell without a nucleus
two cells, each cell with half of the genetic material of the parent cell
one cell with one nucleus containing half of the genetic material of the parent cell
one cell with two nuclei, each identical to the nucleus of the parent cell
Humans produce skin cells by mitosis and gametes by meiosis. The nuclei of skin cells produced by mitosis will have...
half as much DNA as the nuclei of gametes produced by meiosis
the same amount of DNA as the nuclei of gametes produced by meiosis
twice as much DNA as the nuclei of gametes produced by meiosis
four times as much DNA as the nuclei of gametes produced by meiosis
Movement of the chromosomes during anaphase would be most affected by a drug that prevents...
nuclear envelope breakdown
cell wall formation
elongation of microtubules
shortening of microtubules
During which phase of mitosis do the chromatids become chromosomes?
telophase
anaphase
prophase
metaphase
A plant-derived protein known as colchicine can be used to poison cells by blocking the formation of the spindle. Which of the following would result if colchicine is added to a sample of cells in G2?
the cells would immediately die
the cells would be unable to begin M and stay in G2
the chromosomes would coil and shorten but have no spindle to which to attach
the chromosomes would segregate but ina disorderly pattern
Which is the first checkpoint in the cell cycle where a cell will be caused to exit the cycle if this point is not passed?
G0
G1
G2
S
Which of the following is a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex?
PDGF
MPF
protein kinase
cyclin
The cyclin component of MPF is destroyed toward the end of which phase?
G0
G1
G2
M
Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called...
ATPases
kinetochores
kinases
cyclins
Which of the following describes cyclin-dependent kinase (Cdk)?
Cdk is inactive, or "turned off," in the presence of cyclin
Cdk is present thoughout the cell cycle
Cdk is an enzyme that attaches phosphate groups to other proteins
Cdk is present throughout the cell cycle and is an enzyme that attaches phosphate groups to other proteins
All cell cycle checkpoints are similar in which way?
they respond to the same cyclins
they give the go-ahead signal to progress to the next checkpoint
they each have only one cyclin/Cdk complex
they activate or inactivate other proteins
You have a series of cells, all of which were derived from tumors, and you first need to find out which ones are malignant. What could you do?
see which ones are not overproliferating
find out which ones have a higher rate of apoptosis
karyotype samples to look for unusual size and number of chromosomes
time their cell cycles
Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely...
an animal cell in the process of cytokinesis
a plant cell in the process of cytokinesis
an animal cell in the S phase of the cell cycle
a plant cell in metaphase
Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?
proto-oncogenes first arose from viral infections
proto-oncogenes normally help regulate cell division
proto-oncogenes are genetic "junk"
cells produce proto-oncogenes as they age
Which of the following statements describes proto-oncogenes?
their normal function is to suppress tumor growth
they are introduced to a cell initially by retroviruses
they are produced by somatic mutations induced by carcinogenic substances
they can code for proteins associated with cell growth
Which of the following is characteristic of the product of the p53 gene?
it is an activator for other genes
it speeds up the cell cycle
it causes cell death via apoptosis
it allows cells to pass on mutations due to DNA damage
Tumor-suppressor genes...
are frequently overexpressed in cancerous cells
are cancer-causing genes introduced into cells by viruses
can encode proteins that promote DNA repair or cell-cell adhesion
often encode proteins that stimulate the cell cycle
do all of the above
