Download BSC1010 Quiz 2 Answers - Palm Beach State College

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BSC1010: Principles of Biology
Spring 2016
Quiz 2 (Chapters 8 – 10)
Read each question CAREFULLY and choose the BEST possible answer. Mark the answer on your
Scantron. You may use this exam to work out any problems. Turn in both this exam and the Scantron
when you are done. Good luck, take a deep breath and begin.
1) Which of the following is true of metabolism in its entirety in all organisms?
A) Metabolism depends on a constant supply of energy from food.
B) Metabolism uses all of an organism's resources.
C) Metabolism consists of all the energy transformation reactions in an organism.
D) Metabolism manages the increase of entropy in an organism.
2) Which term most precisely describes the cellular process of breaking down large molecules into
smaller ones?
A) catabolism (catabolic pathways)
B) metabolism
C) anabolism (anabolic pathways)
D) dehydration
3) Which of the following is a statement of the first law of thermodynamics?
A) Energy cannot be created or destroyed.
B) The entropy of the universe is decreasing.
C) The entropy of the universe is constant.
D) Energy cannot be transferred or transformed.
4) Which of the following statements is representative of the second law of thermodynamics?
A) Conversion of energy from one form to another is always accompanied by some gain of free energy.
B) Without an input of energy, organisms would tend toward decreasing entropy.
C) Cells require a constant input of energy to maintain their high level of organization.
D) Every energy transformation by a cell decreases the entropy of the universe.
5) Which of the following types of reactions would decrease the entropy within a cell?
A) anabolic reactions
B) hydrolysis
C) digestion
D) catabolic reactions
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6) The mathematical expression for the change in free energy of a system is ΔG =ΔH - TΔS. Which of the
following is correct?
A) ΔS is the change in enthalpy, a measure of randomness.
B) ΔH is the change in entropy, the energy available to do work.
C) ΔG is the change in free energy.
D) T is the temperature in degrees Celsius.
7) A chemical reaction that has a positive ΔG is best described as _____.
A) enthalpic
B) endergonic
C) spontaneous
D) exergonic
8) Why is ATP an important molecule in metabolism?
A) Its hydrolysis provides an input of free energy for exergonic reactions.
B) It provides energy coupling between exergonic and endergonic reactions.
C) Its terminal phosphate group dissolves in water.
D) Its terminal phosphate bond has higher energy than the other two phosphate bonds.
9) When chemical, transport, or mechanical work is done by an organism, what happens to the heat
generated?
A) It is used to power yet more cellular work.
B) It is used to store energy as more ATP.
C) It is used to generate ADP from nucleotide precursors.
D) It is lost to the environment.
10) When ATP releases some energy, it also releases inorganic phosphate. What happens to the inorganic
phosphate in the cell?
A) It is secreted as waste.
B) It is used only to regenerate more ATP.
C) It may be used to form a phosphorylated intermediate.
D) It enters the nucleus and affects gene expression.
11) How do cells use the ATP cycle shown in the figure?
A) Cells use the cycle to recycle ADP and phosphate.
B) Cells use the cycle to recycle energy released by ATP hydrolysis.
C) Cells use the cycle to recycle ADP, phosphate, and the energy released by ATP hydrolysis.
D) Cells use the cycle primarily to generate heat.
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12) Which of the following is true of enzymes?
A) Enzyme function is increased if the 3- D structure or conformation of an enzyme is altered.
B) Enzyme function is independent of physical and chemical environmental factors such as pH and temperature.
C) Enzymes increase the rate of chemical reaction by lowering activation energy barriers.
D) Enzymes increase the rate of chemical reaction by providing activation energy to the substrate.
13) A noncompetitive inhibitor decreases the rate of an enzyme reaction by _____.
A) binding at the active site of the enzyme
B) changing the shape of the enzyme's active site
C) changing the free energy change of the reaction
D) acting as a coenzyme for the reaction
Activity of various enzymes at various temperatures (a) and at various pH (b).
14) Which curves 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?
A) curves 1 and 5
B) curves 2 and 5
C) curves 3 and 4
D) curves 3 and 5
15) 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) curves 1 and 5
C) curves 2 and 4
D) curves 3 and 4
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The following questions are based on the reaction A + B ↔ C + D shown in the accompanying figure.
16) Which of the following terms best describes the forward reaction in the figure?
A) endergonic, ∆G > 0
B) exergonic, ∆G < 0
C) endergonic, ∆G < 0
D) exergonic, ∆G > 0
17) Which of the following in the figure would be the same in either an enzyme-catalyzed or a
noncatalyzed reaction?
A) a
B) b
C) c
D) d
18) Which of the following represents the activation energy required for the enzyme-catalyzed reaction in
the figure?
A) a
B) b
C) c
D) d
19) When electrons move closer to a more electronegative atom, what happens? The more electronegative
atom is _____.
A) reduced, and energy is released
B) reduced, and energy is consumed
C) oxidized, and energy is consumed
D) oxidized, and energy is released
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20) Which of the listed statements describes the results of the following reaction?
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
A) C6H12O6 is oxidized and O2 is reduced.
B) O2 is oxidized and H2O is reduced.
C) CO2 is reduced and O2 is oxidized.
D) O2 is reduced and CO2 is oxidized.
21) When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton),
the molecule becomes _____ to NADH.
A) dehydrogenated
B) oxidized
C) reduced
D) redoxed
22) 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 pyruvate, and 2 ATP
23) Which electron carrier(s) function in the citric acid cycle?
A) NAD+ only
B) NADH and FADH2
C) the electron transport chain
D) ADP and ATP
24) Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?
A) glycolysis and the oxidation of pyruvate to acetyl CoA
B) fermentation and glycolysis
C) oxidative phosphorylation and fermentation
D) oxidation of pyruvate to acetyl CoA and the citric acid cycle
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Use the following figure to answer the questions below.
The citric acid cycle.
25) For each mole of glucose (C6H12O6) oxidized by cellular respiration, how many moles of CO2 are
released in the citric acid cycle (see the accompanying figure)?
A) 2
B) 4
C) 6
D) 32
26) If pyruvate oxidation is blocked, what will happen to the levels of oxaloacetate and citric acid in the
citric acid cycle shown in the accompanying figure?
A) Oxaloacetate will decrease and citric acid will accumulate.
B) Oxaloacetate will accumulate and citric acid will decrease.
C) Both oxaloacetate and citric acid will decrease.
27) Starting with citrate, which of the following combinations of products would result from three acetyl
CoA molecules entering the citric acid cycle (see the accompanying figure)?
A) 1 ATP, 2 CO2, 3 NADH, and 1 FADH2
B) 3 ATP, 3 CO2, 3 NADH, and 3 FADH2
C) 3 ATP, 6 CO2, 9 NADH, and 3 FADH2
D) 38 ATP, 6 CO2, 3 NADH, and 12 FADH2
28) The electron transport chain _____.
A) is a series of redox reactions
B) is a series of substitution reactions
C) is driven by ATP consumption
D) takes place in the cytoplasm of prokaryotic cells
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29) In chemiosmosis, what is the most direct source of energy that is used to convert ADP + i to ATP?
A) energy released as electrons flow through the electron transport system
B) energy released from substrate-level phosphorylation
C) energy released from movement of protons through ATP synthase, down their electrochemical gradient
D) No external source of energy is required because the reaction is exergonic.
30) In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of
_____.
A) ATP, CO2, and ethanol (ethyl alcohol)
B) ATP, CO2, and lactate
C) ATP, NADH, and pyruvate
D) ATP, pyruvate, and acetyl CoA
31) During lactic acid fermentation, pyruvate is reduced directly by NADH to form lactate without the
release of CO2, the resulting process is ______.
A) used by some fungi and yeast utilize the process to make cheese and yogurt
B) human muscle cells switch from aerobic respiration to lactic acid fermentation when O2 is scarce
C) ATP is formed in an alternative manner from sugars
D) all of the above
32) Which of the above processes accounts for most of the ATP production in the Cellular Respiration
process?
A) Glycolysis
B) Citric acid Cycle
C) Oxydative Phosphorylation
D) They each produce ATP in equal amounts.
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33) Ancient prokaryotes are thought to have used glycolysis long before there was oxygen in the
atmosphere, the reason for this is thought to be that ___________.
A) Glycolysis is a very new process
B) Very little O2 was available in the atmosphere until about 2.7 billion years ago, so early prokaryotes likely
used only glycolysis to generate ATP
C) Eukaryotes were competing for the atmospheric oxygen and the prokaryotes needed to have alternative
pathways in order to compete.
D) Sulfur was too toxic to utilize in the biological process
34) Glycolysis follows the pathway of breaking sugar down to utilize the energy released to produce
ATP. These processes can also utilize _____.
A) Other sugars and carbohydrates
B) Proteins
C) Fats and fatty acids
D) All of these
35) 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) During aerobic respiration, muscle cells cannot produce enough lactate to fuel muscle cell contractions and
muscles begin to cramp, thus athletic performance suffers.
B) During anaerobic respiration, lactate levels increase when muscles cells need more energy, however muscles
cells eventually fatigue, thus athletes should modify their activities to increase aerobic respiration.
C) During aerobic respiration, muscles cells produce too much lactate which causes a rise in the pH of the
muscle cells, thus athletes must consume increased amounts of sports drinks, high in electrolytes, to buffer the
pH.
D) During anaerobic respiration, muscle cells receive too little oxygen and begin to convert lactate to pyruvate
(pyruvic acid), thus athletes experience cramping and fatigue.
36) Which of the following statements is a correct distinction between autotrophs and heterotrophs?
A) Cellular respiration is unique to heterotrophs.
B) Only heterotrophs have mitochondria.
C) Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are
inorganic.
D) Only heterotrophs require oxygen.
37) 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; respiration releases energy from complex
organic molecules
C) Photosynthesis occurs only in plants; respiration occurs only in animals.
D) Photosynthesis is catabolic; respiration is anabolic.
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Use the following figure to answer the questions below.
38) What wavelength of light in the figure is most effective in driving photosynthesis?
A) 420 mm
B) 575 mm
C) 625 mm
D) 730 mm
39) 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?
A) green
B) blue
C) orange
D) Any color will work equally well.
40) What is the primary function of the Calvin cycle?
A) use NADPH to release carbon dioxide
B) split water and release oxygen
C) transport RuBP out of the chloroplast
D) synthesize simple sugars from carbon dioxide
41) Which of the following does NOT occur during the Calvin cycle?
A) oxidation of NADPH
B) release of oxygen
C) regeneration of the CO2 acceptor
42) What compound provides the reducing power for Calvin cycle reactions?
A) ATP
B) NADH
C) NADP+
D) NADPH
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Use the accompanying figure and the molecules labeled A, B, C, D, and E to answer the following
questions.
43) Refer to the figure. If the carbon atom of each of the incoming CO2 molecules is labeled with a
radioactive isotope of carbon, which organic molecules will be radioactively labeled after one cycle?
A) C only
B) B, C, D, and E
C) C, D, and E only
D) B and C only
44) How many turns of the Calvin Cycle will it take to produce one molecule of Glucose
A) 2
B) 3
C) 6
D) 12
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45) CAM plants keep stomata closed in the daytime, thus reducing loss of water. They can do this because
they _____.
A) fix CO2 into organic acids during the night
B) fix CO2 into sugars in the bundle-sheath cells
C) fix CO2 into pyruvate in the mesophyll cells
D) use photosystem I and photosystem II at night
Use the following figure to answer the questions below.
46) Which of the following statements is true concerning the accompanying figure?
A) It represents a C4 photosynthetic system.
B) It represents an adaptation that maximizes photorespiration.
C) It represents a C3 photosynthetic system.
D) It represents a CAM photosynthetic system.
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Use the following diagram to answer the following questions and fill in the appropriate parts of the
reactions.
47
49
48
50
47) Represents which of the following:
A) CO2
B) H20
C) [CH2O] sugar
D) O2
48) Represents which of the following:
A) CO2
B) H20
C) [CH2O] sugar
D) O2
49) Represents which of the following:
A) CO2
B) H20
C) [CH2O] sugar
D) O2
50) Represents which of the following:
A) CO2
B) H20
C) [CH2O] sugar
D) O2
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