Biology Final
Substrate-level phosphorylation occurs _____.
B
The electron transport chain _____.
B
A cell has enough available ATP to meet its needs for about 30 seconds. What is likely to happen when an athlete exhausts his or her ATP supply?
A
New biosensors, applied like a temporary tattoo to the skin, can
alert serious athletes that they are about to "hit the wall"
and find it difficult to continue exercising. These biosensors monitor
lactate, a form of lactic acid, released in sweat during strenuous
exercise.
Which of the statements below is the best
explanation of why athletes would need to monitor lactate levels?
A
Which of the listed statements describes the results of the following
reaction?
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
D
Following glycolysis and the citric acid cycle, but before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is in the form of _____.
C
Which process is most directly driven by light energy?
C
In its mechanism, photophosphorylation is most similar to _____.
B
In autumn, the leaves of deciduous trees change colors. This is because chlorophyll is degraded and _____.
C
In a plant, the reactions that produce molecular oxygen (O2) take place in _____.
D
What would be the expected effect on plants if the atmospheric CO2 concentration was doubled?
B
Suppose a plant has a unique photosynthetic pigment and the leaves of this plant appear to be reddish yellow. What wavelengths of visible light are absorbed by this pigment?
C
Why are there several structurally different pigments in the reaction centers of photosystems?
B
Cells from advanced malignant tumors often have very abnormal chromosomes and an abnormal number of chromosomes. What might explain the association between malignant tumors and chromosomal abnormalities?
D
Motor proteins require which of the following to function in the movement of chromosomes toward the poles of the mitotic spindle?
C
In eukaryotic cells, chromosomes are composed of _____.
A
Metaphase is characterized by _____.
D
MPF is a dimer consisting of _____.
C
Kinetochore microtubules assist in the process of splitting centromeres by _____.
A
The M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does not happen, cells would most likely be arrested in _____.
B
Starting with a fertilized egg (zygote), a series of five cell
divisions would produce an early embryo with how many cells?
A)
4
B) 8
C) 16
D) 32
E) 64
D
At which phase are centrioles beginning to move apart in animal
cells?
A) telophase
B) anaphase
C)
prometaphase
D) metaphase
E) prophase
E
If there are 20 centromeres in a cell at anaphase, how many
chromosomes are there in each daughter cell following cytokinesis?
A) 10
B) 20
C) 30
D) 40
E) 80
A
Taxol is an anticancer drug extracted from the Pacific yew tree. In
animal cells, Taxol disrupts microtubule formation by binding to
microtubules and accelerating their assembly from the protein
precursor, tubulin. Surprisingly, this stops mitosis. Specifically,
Taxol must affect
A) the formation of the mitotic
spindle.
B) anaphase.
C) formation of the centrioles.
D) chromatid assembly.
E) the S phase of the cell cycle.
A
During which phase of mitosis do the chromatids become chromosomes?
A) telophase
B) anaphase
C) prophase
D) metaphase
E) cytokinesis
A
Which of the following is released by platelets in the vicinity of an
injury?
A) PDGF
B) MPF
C) protein kinase
D) cyclin
E) Cdk
A
Which of the following triggers the cell's passage past the G₂
checkpoint into mitosis?
A) PDGF
B) MPF
C) protein
kinase
D) cyclin
E) Cdk
B
For a chemotherapeutic drug to be useful for treating cancer cells,
which of the following is most desirable?
A) It is safe enough
to limit all apoptosis.
B) It does not alter metabolically
active cells.
C) It only attacks cells that are density
dependent.
D) It interferes with cells entering G₀.
E) It
interferes with rapidly dividing cells.
E
Which of the following does not occur during mitosis?
A)
condensation of the chromosomes
B) replication of the DNA
C) separation of sister chromatids
D) spindle formation
E) separation of the spindle poles
B
The drug cytochalasin B blocks the function of actin. Which of the
following aspects of the cell cycle would be most disrupted by
cytochalasin B?
A) spindle formation
B) spindle attachment
to kinetochores
C) DNA synthesis
D) cell elongation during
anaphase
E) cleavage furrow formation and cytokinesis
E
Which of the following are directly associated with photosystem I?
A) harvesting of light energy by ATP
B) receiving
electrons from the thylakoid membrane electron transport chain
C) generation of molecular oxygen
D) extraction of
hydrogen electrons from the splitting of water
E) passing
electrons to the thylakoid membrane electron transport chain
B
In a plant cell, where are the ATP synthase complexes located?
A) thylakoid membrane only
B) plasma membrane only
C) inner mitochondrial membrane only
D) thylakoid membrane
and inner mitochondrial membrane
E) thylakoid membrane and
plasma membrane
D
Which of the following statements best describes the relationship
between photosynthesis and respiration?
A) Respiration runs the
biochemical pathways of photosynthesis in reverse.
B)
Photosynthesis stores energy in complex organic molecules, whereas
respiration releases it.
C) Photosynthesis occurs only in plants
and respiration occurs only in animals.
D) ATP molecules are
produced in photosynthesis and used up in respiration.
E)
Respiration is anabolic and photosynthesis is catabolic.
B
In photosynthetic cells, synthesis of ATP by the chemiosmotic
mechanism occurs during
A) photosynthesis only.
B)
respiration only.
C) both photosynthesis and respiration.
D) neither photosynthesis nor respiration.
E)
photorespiration only.
C
Carotenoids are often found in foods that are considered to have
antioxidant properties in human nutrition. What related function do
they have in plants?
A) They serve as accessory pigments to
increase light absorption.
B) They protect against oxidative
damage from excessive light energy.
C) They shield the sensitive
chromosomes of the plant from harmful ultraviolet radiation.
D)
They reflect orange light and enhance red light absorption by
chlorophyll.
E) They take up and remove toxins from the groundwater.
B
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.
A) The
dissolved oxygen in the flask with algae will always be higher.
B) The dissolved oxygen in the flask with algae will always be
lower.
C) The dissolved oxygen in the flask with algae will be
higher in the light, but the same in the dark.
D) The dissolved
oxygen in the flask with algae will be higher in the light, but lower
in the dark.
E) The dissolved oxygen in the flask with algae
will not be different from the control flask at any time.
D
Why are C₄ plants able to photosynthesize with no apparent
photorespiration?
A) They do not participate in the Calvin
cycle.
B) They use PEP carboxylase to initially fix CO₂.
C) They are adapted to cold, wet climates.
D) They
conserve water more efficiently.
E) They exclude oxygen from
their tissues.
B
Compared to C₃ plants, C₄ plants
A) can continue to fix CO₂
even at relatively low CO2 concentrations and high oxygen
concentrations.
B) have higher rates of photorespiration.
C) do not use rubisco for carbon fixation.
D) grow better
under cool, moist conditions.
E) make a four-carbon compound,
oxaloacetate, which is then delivered to the citric acid cycle in mitochondria.
A
In mechanism, photophosphorylation is most similar to
A)
substrate-level phosphorylation in glycolysis.
B) oxidative
phosphorylation in cellular respiration.
C) the Calvin cycle.
D) carbon fixation.
E) reduction of NADP⁺.
B
Which process is most directly driven by light energy?
A)
creation of a pH gradient by pumping protons across the thylakoid
membrane
B) carbon fixation in the stroma
C) reduction of
NADP⁺ molecules
D) removal of electrons from chlorophyll
molecules
E) ATP synthesis
D
When electrons move closer to a more electronegative atom, what
happens?
A) The more electronegative atom is reduced, and energy
is released.
B) The more electronegative atom is reduced, and
energy is consumed.
C) The more electronegative atom is
oxidized, and energy is consumed.
D) The more electronegative
atom is oxidized, and energy is released.
E) The more
electronegative atom is reduced, and entropy decreases.
A
When a molecule of NAD⁺ (nicotinamide adenine dinucleotide) gains a
hydrogen atom (not a proton), the molecule becomes
A)
dehydrogenated.
B) oxidized.
C) reduced.
D) redoxed.
E) hydrolyzed.
C
The free energy for the oxidation of glucose to CO₂ and water is -686
kcal/mol and the free energy for the reduction of NAD⁺ to NADH is +53
kcal/mol. Why are only two molecules of NADH formed during glycolysis
when it appears that as many as a dozen could be formed?
A) Most
of the free energy available from the oxidation of glucose is used in
the production of ATP in glycolysis.
B) Glycolysis is a very
inefficient reaction, with much of the energy of glucose released as
heat.
C) Most of the free energy available from the oxidation of
glucose remains in pyruvate, one of the products of glycolysis.
D) There is no CO₂ or water produced as products of glycolysis.
E) Glycolysis consists of many enzymatic reactions, each of
which extracts some energy from the glucose molecule.
C
Starting with one molecule of glucose, the energy-containing products
of glycolysis are
A) 2 NAD⁺, 2 pyruvate, and 2 ATP.
B) 2
NADH, 2 pyruvate, and 2 ATP.
C) 2 FADH₂, 2 pyruvate, and 4 ATP.
D) 6 CO₂, 2 ATP, and 2 pyruvate.
E) 6 CO₂, 30 ATP, and 2 pyruvate.
B
In glycolysis, for each molecule of glucose oxidized to pyruvate
A) two molecules of ATP are used and two molecules of ATP are
produced.
B) two molecules of ATP are used and four molecules of
ATP are produced.
C) four molecules of ATP are used and two
molecules of ATP are produced.
D) two molecules of ATP are used
and six molecules of ATP are produced.
E) six molecules of ATP
are used and six molecules of ATP are produced.
B
During aerobic respiration, H₂O is formed. Where does the oxygen atom
for the formation of the water come from?
A) carbon dioxide
(CO₂)
B) glucose (C₆H₁₂O₆)
C) molecular oxygen (O₂)
D) pyruvate (C₃H₃O₃-)
E) lactate (C₃H₅O₃-)
C
The synthesis of ATP by oxidative phosphorylation, using the energy
released by movement of protons across the membrane down their
electrochemical gradient, is an example of
A) active transport.
B) an endergonic reaction coupled to an exergonic reaction.
C) a reaction with a positive ΔG .
D) osmosis.
E)
allosteric regulation.
B
Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in
A) all cells, but only in the presence of oxygen.
B) only
eukaryotic cells, in the presence of oxygen.
C) only in
mitochondria, using either oxygen or other electron acceptors.
D) all respiring cells, both prokaryotic and eukaryotic, using
either oxygen or other electron acceptors.
E) all cells, in the
absence of respiration.
D
In the presence of oxygen, the three-carbon compound pyruvate can be
catabolized in the citric acid cycle. First, however, the pyruvate (1)
loses a carbon, which is given off as a molecule of CO₂, (2) is
oxidized to form a two-carbon compound called acetate, and (3) is
bonded to coenzyme A.
These three steps result in the formation of
A) acetyl
CoA, O₂, and ATP.
B) acetyl CoA, FADH₂, and CO₂.
C) acetyl
CoA, FAD, H₂, and CO₂.
D) acetyl CoA, NADH, H⁺, and CO₂.
E) acetyl CoA, NAD⁺, ATP, and CO₂.
D