Biology, Eighth Edition (Raven)

Chapter 7: How Cells Harvest Energy

Post Test

1
Why does NAD+ serve as important electron carrier? (p. 121)
A)It is readily reduced and oxidized.
B)It is insoluble and is stationary within the cell.
C)It can accept electrons in a variety of positions along its length.
D)It "protects" electrons from winding up in fatty acid precursors where the energy would be wasted.
E)All of the above are correct.
2
What products result from the complete oxidation of glucose? (p. 124)
A)CO2
B)ATP
C)NADH
D)FADH2
E)All of these result from glucose oxidation.
3
Why must NAD+ be present during glycolysis? (p. 125)
A)It creates pyruvate directly from glucose.
B)A glycolysis intermediate must be oxidized in order to receive a phosphate so that substrate-level phosphorylation may occur.
C)It powers the electron transport chain.
D)It is a coenzyme which allows the 6 carbons of glucose to separate from each other, leading to two three-carbon products.
E)This is a trick question: NAD+ is only involved in the Krebs cycle.
4
What is/are the product(s) of pyruvate oxidation? (p. 128)
A)O2
B)Acetyl-CoA
C)NAD+
D)ATP
E)All of the above are created during pyruvate oxidation
5
How many CO2 molecules are released specifically from the Krebs cycle for each glucose molecule consumed? (p. 131)
A)1
B)2
C)3
D)4
E)6
6
Suppose the F1 complexes (catalytic heads) of ATP synthase are all enzymatically removed (say, by cutting the stalk which holds it to the F0 transmembrane region). What consequence is most logical? (p. 133)
A)Negative feedback will be decreased, causing faster ATP production.
B)The electron transport chain will slow down.
C)The cell will have no mechanism to make ATP and will die.
D)Protons will quickly equilibrate between the matrix and intermembrane space.
E)All of the above will occur.
7
For one molecule of glucose, what is the maximum number of ATP molecules created directly from the Krebs cycle? (p. 134)
A)1
B)2
C)3
D)4
E)5
8
What is the name of the mechanism by which pyruvate dehydrogenase is inhibited by the end-product of the biochemical pathway? (p. 135)
A)Anabolism
B)Catabolism
C)Regulation
D)Negative inhibition
E)Regurgitation
9
When yeast ferment a product, they create CO2, but animal cells do not. What is the difference in their fermentation strategies? (p. 136)
A)Yeast prefer to make ethanol.
B)Ethanol has two carbons, while lactate has three.
C)Yeast get more energy when they ferment than do animals.
D)Animals have a central nervous system which allows for better metabolic decisions.
E)Yeast are protists, and do things differently than more-evolved creatures such as animals.
10
Some diet regimens claim to operate by excluding some chemicals from the food consumed. People who abstain from eating certain foods don't simply run out of energy and die. Choose the most plausible answer for why they don't. (p. 139)
A)They create all the enzymes they need after ingesting the food.
B)Macromolecules have an inherent property of stimulating the enzymes required for their degradation for energy.
C)Oxidation pathways of food molecules are interrelated to such an extent that enzymes can link their breakdown from different starting points.
D)Life is so inventive and versatile that natural selection can take over and bind organic pathways to allow the organism to survive.
E)The genetic instructions in an organism are so complex that it's possible to create new enzymes when required.
11
Which of the following argues most strongly for glycolysis as one of the most primitive biochemical pathway? (p. 140)
A)It does not require oxygen in order to function.
B)It occurs in the cytoplasm of cells.
C)It is exergonic, and therefore obeys the laws of thermodynamics which are fundamental to chemistry and physics.
D)The amino acid sequence for enzymes of this pathway are almost identical in all living creatures.
E)There is no evidence that glycolysis is primitive
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