BIO 311c
Answer Key to Sample Exam 3
K. Sathasivan
BIO 311c Introductory Biology
K. Sathasivan Spring 2015
ANSWER KEY TO SAMPLE EXAM 3
Part A. Multiple Choice Questions. Read carefully and answer all the 26 questions.
The best 25 questions will be used for a maximum of 50 points (2.0 points each)
1) Which of the following reactions will have the lowest vMax and lowest Km when appropriate
substrate is used at right temperature?
A) Enzyme alone
B) Enzyme + substrate
C) Enzyme + substrate + activator
D) Enzyme + substrate + competitive inhibitor
E) Enzyme + substrate + non-competitive inhibitor
2) Citrate binds to the regulatory site of the key regulatory enzyme PFK to inhibit Glycolysis
whereas the substrates bind to the catalytic site. This effect of citrate is an example of
A) competitive inhibition.
B) non-competitive inhibition.
C) cooperative inhibition.
D) chemical modification.
E) enzyme activation.
3) ATP Hydrolysis yields 7.3 Kcal/mol free energy (-7.3 Kcal/mol) and it is coupled with many
enzyme reactions that would not otherwise happen. Which of the following reaction can be
coupled with ATP hydrolysis to become a spontaneous reaction? A reaction with a ΔG value
of _______ Kcal/mol.
A) 7.3
B) 5.3
C) 10.5
D) 8
E) -6
4)
An example of an exergonic and exothermic reaction is _______________.
A) Photosynthesis
B) DNA replication
C) Transcription
D) ATP synthesis
E) Osmosis
5) Energy is stored in the form of ________ in the food we eat.
A) Citrate
B) Covalent bonds
C) Fructose
D) NADH
E) ATP
6)
A)
B)
C)
D)
E)
Which of the following process is the most primitive and occurs under both aerobic and
anaerobic conditions?
Krebs cycle
Oxidative phosphorylation
Lactic acid fermentation
Alcohol fermentation
Glycolysis
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BIO 311c
7)
Answer Key to Sample Exam 3
K. Sathasivan
+
In this reaction, NADH + Pyruvate à NAD + Lactate, Pyruvate becoming Lactate, is a/an
__________________ process and ___________ is the oxidizing or reducing agent.
+
A) reduction…. NAD …oxidizing
B) oxidation…..Pyruvate….reducing
C) reduction… Lactate…reducing
D) reduction…. NADH …reducing
E) oxidation…. FAD …oxidizing
8) The reaction shown below is a/an ___________________ and it is catalyzed by _______.
Creatine-phosphate + ADP à Creatine + ATP
A) reduction…. kinase
B) photophosphorylation…..phosphatase
C) substrate level phosphorylation…….kinase
D) oxidative phosphorylation…….ATP synthase
E) substrate level phosphorylation…….ATP synthase
9)
The outputs of glycolysis include ATP, ________ and _________.
A) Glyceraldehyde 3-phosphate and dihydroxy acetone phosphate.
B) Acetyl CoA and NADH
C) NADH and pyruvate.
D) Pyruvate and NAD+.
E) FADH2 and NADH
10)
The outputs of oxidative phosphorylation that returns to Krebs Cycle are
A) ATP and NADPH
B) CO2 and NADPH
C) FADH2 and NADH
D) NADH and ATP
+
E) FAD and NAD
11) More free energy is released during the Krebs cycle than during glycolysis, but only 2 moles
of ATP is produced for each mole of glucose undergoing glycolysis. Most of the remaining
free energy that is produced during the Krebs cycle is used to
A) synthesize GTP.
+
B) reduce NAD and FAD.
C) release as heat.
D) oxidize pyruvate.
E) make ethanol.
12) Which of the following enables the generation of Δ [H+]?
A) A poison that would inhibit ATP synthase.
B) Oxidation of NADH and FADH2 resulting in electron transfer.
C) Cyanide like chemical that would block the electron transfer
D) ATP hydrolysis
E) ATP synthesis
13) Each FADH2 produces less ATP when compared to NADH in oxidative phosphorylation
because _________________
A) NADH carries 4 electrons whereas FADH2 carries only 2 electrons.
B) NADH carries 2 electrons whereas FADH2 carries only 1 electron.
C) FADH2 gives electrons at a higher energy level to the ETC but still makes less ATP.
D) FADH2 gives electrons at a lower energy level to the ETC and hence makes less ATP.
E) NADH is larger than FADH2
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BIO 311c
Answer Key to Sample Exam 3
K. Sathasivan
14) What is directly responsible to generate the proton concentration gradient in
photophosphorylation?
A) Absorption of light energy by chlorophyll
B) Splitting of water
C) Flow of electrons from photosystem II to photosystem I
D) Reduction of NADP+
E) Synthesis of ATP
15) When a suspension of algal cells is incubated in a flask in the presence of light and CO2 and
then transferred to the dark, the release of oxygen stops. This reaction stops when the algal
suspension is placed in the dark because
A) the reaction requires CO2.
B) the reaction needs light.
C) the reaction requires ATP and NADPH.
D) the reaction requires O2.
E) PSII is not synthesized in the dark.
16) All of the following are directly associated with photosystem II except
A) release of oxygen.
B) harvesting of light energy by chlorophyll and other pigments
C) reaction center chlorophyll
D) CO2 fixation by RuBisCO
E) primary electron acceptor
17) Synthesis and transport of sugars out of leaf occur in __________ and through
_____________ respectively in plants.
A) stroma and stoma
B) leaf and stem
C) stroma and phloem
D) phloem and xylem
E) chloroplast and mitochondrion
18) When the photophosphorylation occurs during light reactions, the pH of the thylakoid interior
will ______________ compared to the equilibrium state during night time.
A) increase
B) decrease
C) stay neutral
D) decrease first and then increase gradually.
E) vary depending on Calvin cycle
19) CAM plants can keep stomata closed in daytime, reducing water loss. This is possible
because they __________.
A) fix CO2 into organic acids during the night by PEP carboxylase.
B) use photosystems I and II during day and night.
C) use the enzyme phosphofructokinase, to fix CO2 more effectively
D) fix CO2 into sugars in the bundle-sheath cells.
E) fix CO2 into pyruvic acid in the mesophyll cells.
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BIO 311c
20)
A)
B)
C)
D)
E)
Answer Key to Sample Exam 3
K. Sathasivan
RuBisCo is regulated by all the following except by______________.
Concentration of O2
Concentration of CO2.
++
Mg
NADPH
Concentration of fructose
21) Why is it important to reduce the chromosome numbers to half the original each time for
sexual reproduction of animals?
A) Sexual reproduction does not need that many chromosomes and less is better.
B) Gametes are sensitive to increased chromosome number.
C) Only the gametes contain double the chromosome number.
D) If the chromosome number gets reduced in meiosis then only a small set of chromosomes
will be needed.
E) When the sperm and egg cells fertilize they double the chromosome number and so we need
to half the chromosome number in the gametes.
22) The homologous chromosomes separate during ____________________ and their sister
chromatids separate during _____________ phase of meiosis.
A) Anaphase I and Telophase I
B) Prophase I and Anaphase II
C) Metaphase I and Metaphase II
D) Anaphase I and Anaphase II
E) Telophase I and Telophase II
23)
A)
B)
C)
D)
E)
The phases of meiosis that cause the most variation in the four daughter cells are
prophase I and telophase II.
prophase I and metaphase I.
prophase II and anaphase II.
metaphase I and telophase II.
anaphase I and prophase II.
24) The initiation of the S phase and the M phase of the cell cycle depends on _______ and
_______ combining to make _______.
A) actin; myosin; fibers
B) Cdk; cyclin; MPF
C) ligand; enzyme; complex
D) insulin; receptor; G-protein
E) ADP; Pi; ATP
25)
A)
B)
C)
D)
E)
Chromosome number is reduced to half the original number during meiosis because
chromosomes do not replicate during the interphase I preceding prophase I.
chromosomes do not replicate between meiosis I and II.
half of the chromosomes from each gamete are lost during fertilization.
sister chromatids separate during anaphase I but not in anaphase II of meiosis.
chromosome numbers are reduced to half during crossing over in prophase I.
26)
A)
B)
C)
D)
E)
The levels of S-cyclin and S-MPF will be at the highest level at the __________.
prophase
end of S-phase
end of M-Phase
beginning of G2 phase
end of G1 phase
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BIO 311c
Answer Key to Sample Exam 3
K. Sathasivan
Part B. Short answer questions. Answer all questions. Maximum points 20.
1) Label the following examples as “exergonic or endergonic” and “exothermic or endothermic”
based on the changes in free energy and enthalpy respectively in each of them. (5 points)
A. Facilitated Diffusion: Exergonic and exothermic
B. Protein synthesis: Endergonic and endothermic
C. Active transport: Endergonic and endothermic
D. ATP hydrolysis: Exergonic and exothermic
E. Photosynthesis: Endergonic and endothermic
2) Draw a bacterial cell and eukaryotic cell (separately) showing the main components needed
for aerobic respiration in each. Label the diagram (in between the two cells) and show the
locations of where the glycolysis, Krebs cycle and oxidative phosphorylation occur in each of
them.
Cell
Glycolysis
Krebs Cycle
Oxidative
Phosphorylation
Bacteria
Cytoplasm
Cytoplasm
Plasma Membrane
Eukaryote
Cytoplasm
Mitochondrial
Matrix
Mitochondrial inner
membrane.
3) Illustrate how the outputs of one process become the inputs of another process in
Photosynthesis. Give two specific names of these two processes and the outputs/inputs
involved (4 points). It is Ok to make a flow chart to explain this.
Process
Outputs
Become
inputs for
the
process
Light
reactions
(noncyclic)
ATP
NADPH
Calvin
Cycle
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BIO 311c
Answer Key to Sample Exam 3
K. Sathasivan
4) A. List 3 major contributions of photosynthesis to human life on this planet? (3 points).
1. Provide supply of food through fixing carbon into carbohydrates and the carbon
skeleton for all other biological molecule.
2. Release oxygen to breath though light reactions.
3. Transportation / fossil fuels derived from the past photosynthetic products in the form
of hydrocarbons.
5) List 3 causes the variations in sexual reproduction and mention during what stage of
sexual reproduction cycle they occur (3 points).
1. Crossing over and genetic recombination in Prophase I
2. Independent assortment in anaphase I and II
3. Random fertilization during/after mating.
6) Make a diagram and label the axes to briefly explain how chromosomal number and
DNA amount will vary in meiosis. (3 points)
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