Deck 9: Cellular Respiration and Fermentation

Question 1

Figure 9.1
Refer to Figure 9.1. What characteristic of this molecule ATP) is responsible for its high energy level compared to AMP?

A) the C-H bonds of the ribose sugar
B) the phosphorus atoms in the phosphate groups
C) the nitrogen atoms in adenine
D) the closely spaced negative charges associated with the phosphate groups

Answer 1

D

Question 2

What electron carriers) function in the Krebs cycle?

A) NAD⁺ only
B) the electron transport chain
C) FAD only
D) both NAD⁺ and FAD

Answer 2

D

Question 3

Which of the following statements concerning cellular metabolism is FALSE?

A) Krebs cycle activity is dependent solely on availability of substrate; otherwise it is unregulated.
B) Reactions of the Krebs cycle take place in the mitochondrial matrix.
C) In the electron transport chain, electrons decrease in energy level as they are transferred from one electron carrier to the next.
D) Glycolysis is inhibited when cellular energy levels are abundant.

Answer 3

A

Question 4

Figure 9.2
Refer to Figure 9.2. Which reactant molecule becomes reduced in the following chemical reaction?
Glyceraldehyde phosphate + NAD⁺ -diphosphoglycerate + NADH + H⁺

A) glyceraldehyde phosphate
B) phosphate
C) NAD⁺
D) the electrons

Question 5

Canine phosphofructokinase PFK) deficiency afflicts springer spaniels, affecting an estimated 10% of the breed. PFK is the glycolytic enzyme that phosphorylates fructose- 1- phosphate and catalyzes the committed step in glycolysis. Given its critical role in glycolysis, one implication of the genetic defect resulting in PFK deficiency in dogs is

A) elevated blood- glucose levels.
B) nothing. It would have no visible effect on the health of the animal.
C) exercise intolerance.
D) early embryonic mortality.

Question 6

Why might adding inorganic phosphate to a reaction mixture where glycolysis was rapidly proceeding help sustain the metabolic pathway?

A) It increases the energy level of the electrons that are transferred to the electron transport chain where ATP is produced.
B) It would increase the oxygen supply available for aerobic respiration because each phosphate group has four oxygen atoms as constituents.
C) The metabolic intermediates of glycolysis are phosphorylated.
D) It would increase the amount of glucose available for catabolism.

Question 7

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) He or she has to sit down and rest.
B) ATP is transported into the cell from circulation.
C) Catabolic processes are activated that generate ATP.
D) Other cells take over and the muscle cell that has used up its ATP quits.

Question 8

Following glycolysis and the Krebs cycle and before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO₂. Most of the energy from the original glucose at that point is still in the form of

A) CO₂.
B) NADH.
C) ATP.
D) H₂O.

Question 9

What is the function of coenzyme A in the Krebs cycle?

A) It is the coenzyme of carboxylation reactions.
B) It is the coenzyme of redox reactions.
C) It is the coenzyme of acetylation reactions.
D) It is a coenzyme of dehydration reactions.

Question 10

A substrate- level phosphorylation occurs in the Krebs cycle where

A) GDP is phosphorylated to produce GTP.
B) acetylation of oxaloacetate takes place.
C) NAD⁺ is phosphorylated to NADH.
D) oxaloacetate is phosphorylated.

Question 11

Which of the following is true of oxidation- reduction redox) reactions?

A) They involve the transfer of one or more carbon atoms from one molecule to another.
B) They allow organisms to convert energy from large macromolecules for cellular use.
C) They allow organisms to convert energy from photons of light for cellular use.
D) B and C are true of redox reactions.
E) A, B, and C are true of redox reactions

Question 12

In the energy- yielding phase of glycolysis, energy is extracted in the form of

A) NADH and ATP.
B) phosphorylated intermediates.
C) carbon dioxide.
D) pyruvate.

Question 13

When one of the eight Krebs cycle intermediates is added to the respiration medium of living cells, like yeast, what happens to the rates of ATP and carbon dioxide production?

A) Rates of ATP and carbon dioxide production both decrease.
B) The rate of ATP production decreases, but the rate of carbon dioxide production increases.
C) The rates of ATP production and carbon dioxide production both increase.
D) There would be no change in ATP production but an increased rate of carbon dioxide production.

Question 14

Which of the following events takes place in the electron transport chain?

A) the breakdown of an acetyl group to carbon dioxide
B) breakdown of glucose into two pyruvate molecules
C) substrate- level phosphorylation
D) the extraction of energy from high- energy electrons remaining from glycolysis and the Krebs cycle

Question 15

A metabolic pathway, glycolysis, is active when cellular energy levels are ; the regulatory enzyme, phosphofructokinase, is _ by ATP.

A) low; inhibited
B) high; activated
C) high; inhibited
D) low; activated

Question 16

The enzyme phosphofructokinase is the major regulatory enzyme of glycolysis. It catalyzes

A) the isomerization of glucose 6- phosphate to fructose 6- phosphate.
B) the phosphorylation of fructose 6- phosphate.
C) the substrate- level phosphorylation reaction whereby phosphoenolpyruvate is converted to pyruvate.
D) the first of the 10 reactions of glycolysis.

Question 17

Two ATP molecules are expended in the energy investment phase of glycolysis. Why is this energy necessary to begin the process of glucose catabolism?

A) It isn't; glucose contains 686 kcal/mole in its chemical bonds, so its catabolism is spontaneous.
B) It is needed to prime the enzymes of glycolysis.
C) Glucose is a stable molecule; thus, some energy must be invested to make the molecule unstable and begin the process of catabolism.
D) It is needed to generate the electron carrier NAD⁺.

Question 18

Figure 9.3
Refer to Figure 9.3. Which of these statements concerning the following reaction is true?
Malate + NAD⁺ -oxaloacetate + NADH + H⁺

A) Malate is more oxidized than oxaloacetate.
B) NAD+ is more reduced than NADH.
C) Malate is more reduced than oxaloacetate.
D) Oxaloacetate is more reduced than malate.

Question 19

The glucose molecule has a great deal of energy in its

A) polar structure.
B) C- N bonds.
C) C- H bonds.
D) number of oxygen atoms.

Question 20

Substrate- level phosphorylation occurs within a metabolic pathway where sufficient energy is released by a given chemical reaction to drive the synthesis of ATP from ADP and phosphate. Substrate- level phosphorylation is seen in which metabolic pathways)?

A) Krebs cycle
B) electron transport chain
C) both glycolysis and the Krebs cycle
D) glycolysis
E) All of the above pathways involve steps where substrate level phosphorylation takes place.

Question 21

Which of the following is FALSE concerning ATP synthase?

A) It generates ATP by chemiosmosis in cellular respiration and photosynthesis.
B) It performs the same function in cellular respiration and photosynthesis, with similar structure and biochemical composition in each.
C) It is a component of the electron transport chain in cellular respiration and photosynthesis.
D) It is an enzyme that is a tiny rotary motor.

Question 22

Fatty acids typically have an even number of carbons. They are catabolized by a process called beta- oxidation. The end- products of the metabolic pathway are acetyl groups of acetyl CoA molecules. What is the most likely fate of the acetyl groups?

A) They directly enter the energy- yielding stages of glycolysis.
B) They directly enter the electron transport chain.
C) They are directly decarboxylated by pyruvate dehydrogenase.
D) They directly enter the Krebs cycle.

Question 23

Which of the following is true in terms of metabolism?

A) Organisms can be classified as either catabolic or anabolic, but not both.
B) Metabolic reactions first appeared in evolutionary history with the appearance of eukaryotes.
C) The reversible reaction ADP + Pi = ATP is linked with other reactions in many metabolic pathways.
D) Oxidation- reduction reactions occur in eukaryotes, but not in bacteria, nor in archaeans.

Question 24

Substrate level phosphorylation occurs in the citric acid cycle when Succinyl CoA is converted to Succinate. Which of the following statements about this event is true?

A) Inorganic phosphate is added to ADP by HS- CoA thereby creating ATP.
B) A phosphate group is removed from HS- CoA and is donated to GDP to form GTP. GTP then donates a phosphate group to ADP to create ATP.
C) Inorganic phosphate is used to create GTP. GTP then donates a phosphate group to ADP to create ATP.

Question 25

The electron transport chain

A) is a series of substitution reactions.
B) is a series of redox reactions.
C) takes place in the cytoplasm of prokaryotic cells.
D) is driven by ATP consumption.

Question 26

After glycolysis, but before the Krebs cycle and electron transport chain/oxidative phosphorylation, most of the energy from the original glucose is in the form of which molecule?

A) pyruvate
B) CO₂ C) ATP
D) NADH
E) H2O

Question 27

The chemiosmotic hypothesis is an important key to understanding general metabolism because

A) it explains how ATP is synthesized by a proton motive force.
B) it explains the reduction of oxygen to water in the final steps of oxidative metabolism.
C) it explains how electron transport can fuel substrate- level phosphorylation.
D) it explains the sequence of the electron transport chain molecules.

Question 28

ATP production by ATP synthase, requiring a proton gradient across a membrane, occurs in which of the following?

A) substrate- level phosphorylation.
B) oxidative phosphorylation
C) photophosphorylation
D) Both A and B.
E) Both B and C

Question 29

Pyruvate oxidation occurs in

A) the cytosol.
B) the mitochondrial inner membrane.
C) the mitochondrial intermembrane space.
D) the mitochondrial matrix.

Question 30

C₆H₁₂O₆ glucose) + 6O₂ -6 CO₂ + 6H₂O
Where is most of the water in this reaction produced?

A) fermentation
B) glycolysis
C) Krebs cycle
D) electron transport chain

Question 31

C₆H₁₂O₆ + 6 O₂ -6 CO₂ + 6 H₂O + Energy
Which of the following statements describes the pathway shown above?

A) It is a pathway that occurs in plants, algae, and some prokaryotes, but not in other organisms such as animals, fungi).
B) It is a catabolic pathway.
C) It is an anabolic pathway.
D) It is a set of reactions, each of which is exergonic.

Question 32

In cellular respiration, electrons are moved along a series of membrane proteins during the electron transport chain. If there was a mutation in the DNA coding for each of the proton pumps of the electron transport chain such that these proteins became non- functional, what would you predict to occur?

A) Protons would not be moved from the matrix to the intermembrane space and so ATP synthase would not be activated.
B) NADH and FADH₂ would have to donate their electrons directly to ATP synthase in order for ATP synthesis to occur.
C) All electrons would have to be stripped from water instead of NADH and FADH2 to create the proton gradient needed to power ATP synthase.
D) Protons would no longer be moved from the intermembrane space to the matrix and so ATP synthase would not be activated.

Question 33

In the figure above, where are the enzymes of the Krebs citric acid) cycle located? Choose the arrow that corresponds.

A) A
B) B
C) C
D) D

Question 34

Which metabolic pathway is common to both cellular respiration and fermentation?

A) oxidative phosphorylation
B) the oxidation of pyruvate to acetyl CoA
C) glycolysis
D) the citric acid cycle
E) chemiosmosis

Question 35

The constituents of the electron transport chain have similar capabilities, with the exception of ubiquinone coenzyme Q). What is different about ubiquinone?

A) Ubiquinone is a protein that begins the electron transport chain. It therefore accepts high- energy electrons.
B) Ubiquinone is a protein that is a constituent of all cells, prokaryotic or eukaryotic; hence its name.
C) Ubiquinone is a protein that serves as a regulator of the speed of redox reactions in the electron transport chain.
D) Ubiquinone is lipid soluble and can therefore move through the inner mitochondrial membrane.

Question 36

Why are fermentation reactions important for cells?

A) They utilize oxygen.
B) They regenerate NAD⁺ so that glycolysis can continue.
C) They generate oxygen.
D) They produce alcohol used in alcoholic beverages.

Question 37

The energy of electron transport serves to move translocate) protons to the outer mitochondrial compartment. How does this help the mitochondrion to produce energy?

A) The protons receive electrons from NAD⁺ and FAD that are accepted in glycolysis and the Krebs cycle.
B) The protons pick up electrons from the electron transport chain on their way through the inner mitochondrial membrane.
C) The translocation of protons sets up the electrochemical gradient that drives ATP synthesis in the mitochondria.
D) The hydrogen ions protons) are transferred to oxygen in an energy- releasing reaction.

Question 38

The inner mitochondrial membrane normally

A) is virtually impermeable to hydrogen ions protons).
B) contains permease channels that allow small ions and water to pass readily through the membrane by simple diffusion.
C) contains an active transport pump that pumps protons into the inner mitochondrial compartment from the point of high concentration to a point of lower concentration.
D) contains enzymes responsible for two of the chemical reactions that take place as part of glycolysis.

Question 39

The ATP made during fermentation is generated by

A) chemiosmosis.
B) oxidative phosphorylation.
C) aerobic respiration.
D) the electron transport chain.
E) substrate- level phosphorylation.

Question 40

During the electron transport chain, cytochrome oxidase catalyzes the transfer for electrons from cytochrome c to oxygen in the mitochondria. Cyanide is a poison that inhibits the enzyme cytochrome oxidase. When cyanide is present, what will happen?

A) Glycolysis will no longer produce pruvate.
B) The electron transport chain will shut down.
C) The Kreb's cycle will no longer synthesize electron carriers.
D) All of the above

Question 41

In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of

A) ATP, NADH, and pyruvate.
B) ATP, CO2, and ethanol ethyl alcohol).
C) ATP, CO2, and lactate.
D) ATP, pyruvate, and acetyl CoA.
E) ATP, pyruvate, and oxygen.

Question 42

A mutation in yeast makes it unable to convert pyruvate to ethanol. How will this mutation affect these yeast cells? The mutant yeast cells will

A) be unable to grow anaerobically.
B) grow anaerobically only when given glucose.
C) metabolize only fatty acids.
D) die because they cannot regenerate NAD+ from NAD.
E) be unable to metabolize glucose.

Question 43

Which of the following occurs in the cytosol of a eukaryotic cell?

A) oxidative phosphorylation
B) citric acid cycle
C) oxidation of pyruvate to acetyl CoA
D) fermentation and chemiosmosis
E) glycolysis and fermentation