Chapter 9: Cellular Respiration and Fermentation

In the absence of oxygen, yeast cells can obtain energy by fermentation, which results in the production of which of the following sets of molecules? A) ATP, CO 2 , and ethanol (ethyl alcohol) B) ATP, CO 2 , and lactate C) ATP, NADH, and ethanol D) ATP, CO 2 , and acetyl CoA

A

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the A) oxidation of glucose and other organic compounds. B) flow of electrons down the electron transport chain. C) H + concentration gradient across the membrane holding ATP synthase. D) transfer of phosphate to ADP.

C

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is A) oxygen. B) water. C) NAD + . D) pyruvate.

A

What happens when electrons are passed from one atom to a more electronegative atom? 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.

A

Which of the following metabolic processes take place in the cytosol of a eukaryotic cell? A) glycolysis and fermentation B) fermentation and chemiosmosis C) oxidation of pyruvate to acetyl CoA D) citric acid cycle

A

Which of the following statements about NAD + is true? A) NAD + is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. B) NAD + has more chemical energy than NADH. C) NAD + can donate electrons for use in oxidative phosphorylation. D) In the absence of NAD + , glycolysis can still function.

A

Carbon dioxide (CO 2 ) is released during which of the following stages of cellular respiration? A) glycolysis and the oxidation of pyruvate to acetyl CoA B) oxidation of pyruvate to acetyl CoA and the citric acid cycle C) oxidative phosphorylation and fermentation D) fermentation and glycolysis

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

B

In mitochondria, exergonic redox reactions A) are the source of energy driving prokaryotic ATP synthesis. B) provide the energy that establishes the proton gradient. C) reduce carbon atoms to carbon dioxide. D) are coupled via phosphorylated intermediates to endergonic processes.

B

Starting with one molecule of glucose, glycolysis results in the net production of which of the following sets of energy-containing products? A) 2 NAD + , 2 pyruvate, and 2 ATP B) 2 NADH, 2 pyruvate, and 2 ATP C) 4 NADH, 2 pyruvate, and 4 ATP D) 6 CO 2 , 2 pyruvate, and 2 ATP

B

The oxygen consumed during cellular respiration is directly involved in which of the following processes or events? A) glycolysis B) accepting electrons at the end of the electron transport chain C) the citric acid cycle D) the oxidation of pyruvate to acetyl CoA

B

Where are the proteins of the electron transport chain located? A) mitochondrial outer membrane B) mitochondrial inner membrane C) mitochondrial intermembrane space D) mitochondrial matrix

B

Which electron carrier(s) function in the citric acid cycle? A) NAD + only B) NADH and FADH 2 C) the electron transport chain D) ADP and ATP

B

Which of the following metabolic processes normally occurs regardless of whether or not oxygen (O 2 ) is present? A) citric acid cycle B) glycolysis C) lactate fermentation D) oxidative phosphorylation

B

Which one of the following is formed by the removal of a carbon (as CO 2 ) from a molecule of pyruvate? A) ATP B) acetyl CoA C) citrate D) water

B

Energy released by the electron transport chain is used to pump H + ions into which location in eukaryotic cells? A) cytoplasm adjacent to the mitochondrial outer membrane B) mitochondrial inner membrane C) mitochondrial intermembrane space D) mitochondrial matrix

C

In chemiosmosis, what is the most direct source of energy that is used to convert ADP + to ATP? A) energy released as electrons flow through the electron transport chain B) energy released from substrate-level phosphorylation C) energy released from movement of protons through ATP synthase, down their electrochemical gradient D) energy released as electrons are transported across the inner mitochondrial membrane

C

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 CO 2 , (2) is oxidized to form a two-carbon compound called acetate, and (3) is bonded to coenzyme A. Which of the following sets of products result from these reactions? A) acetyl CoA, O 2 , and ATP B) acetyl CoA, FADH 2 , and CO 2 C) acetyl CoA, NADH, and CO 2 D) acetyl CoA, NAD + , ATP, and CO 2

C

The enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis. PFK is inhibited by high levels of which of the following molecules? A) glucose and NAD + B) AMP and ATP C) ATP and citrate D) citrate and CO 2

C

Water is one of the end products of aerobic respiration. What is the source of the oxygen atom used in formation of the water? A) carbon dioxide (CO 2 ) B) glucose (C 6 H 12 O 6 ) C) molecular oxygen (O 2 ) D) pyruvate (C 3 H 3 O 3 - )

C

What happens to a glucose molecule when it loses a hydrogen atom as the result of an oxidation-reduction reaction? A) The glucose molecule is hydrolyzed. B) The glucose molecule is an oxidizing agent. C) The glucose molecule is oxidized. D) The glucose molecule is reduced.

C

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

C

Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? A) the citric acid cycle B) the electron transport chain C) glycolysis D) reduction of pyruvate to lactate

C

Which of the following events takes place in the electron transport chain? A) the breakdown of glucose into six carbon dioxide molecules B) the breakdown of an acetyl group to carbon dioxide C) the harnessing of energy from high-energy electrons derived from glycolysis and the citric acid cycle D) substrate-level phosphorylation

C

Which of the following statements about the electron transport chain is true? A) It is driven by ATP hydrolysis. B) It includes a series of hydrolysis reactions associated with mitochondrial membranes. C) It consists of a series of redox reactions D) It occurs in the cytoplasm of both prokaryotic and eukaryotic cells.

C

Why are carbohydrates and fats frequently considered high-energy foods? A) They contain many oxygen atoms. B) They contain no nitrogen atoms. C) They contain many electrons associated with hydrogen atoms. D) They are strong oxidizing molecules.

C

) In which reactions of cellular respiration and fermentation does substrate-level phosphorylation occur? A) only in glycolysis B) only in the citric acid cycle C) only in the electron transport chain D) in both glycolysis and the citric acid cycle

D

Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C 6 H 12 O 6 ) in aerobic cellular respiration? A) 2 B) 4 C) 18-24 D) 30-32

D

Beta oxidation generates substrates for cellular respiration through which of the following processes? A) catabolism of glucose B) catabolism of glycogen C) catabolism of proteins D) catabolism of fatty acids

D

During aerobic respiration, which of the following molecules directly donates electrons to the electron transport chain at the lowest energy level? A) NADH B) ATP C) water D) FADH 2

D

During which of the following metabolic processes is most of the CO 2 from the catabolism of glucose is released? A) glycolysis B) electron transport C) oxidation of pyruvate to acetyl-CoA D) the citric acid cycle

D

Fatty acids usually have an even number of carbons in their structures. Catabolism of fatty acids produces two-carbon fragments that are converted to acetyl CoA molecules. What is the most likely way in which these acetyl CoA molecules would be metabolized in aerobic cellular respiration? A) They would directly enter the electron transport chain. B) They would directly enter the energy-yielding phase of glycolysis. C) They would be converted to pyruvate and then undergo pyruvate oxidation upon transport into mitochondria. D) They would directly enter the citric acid cycle.

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 CO 2 with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is stored in the form of which of the following molecules? A) acetyl-CoA B) NAD + C) pyruvate D) NADH

D

What kinds of cells carry out ATP synthesis by chemiosmosis? A) all cells, both prokaryotic and eukaryotic, exclusively using oxygen as the electron acceptor B) only animal cells in mitochondria, exclusively using oxygen as the electron acceptor C) only eukaryotic cells, both plant and animal, using either oxygen or other electron acceptors D) all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors

D

Which of the following processes generates a proton-motive force in mitochondria? A) the flow of protons through ATP synthase down their concentration gradient B) the reduction of NAD + by the first electron carrier in the electron transport chain C) lowering of pH in the mitochondrial matrix i D) pumping of hydrogen ions from the mitochondrial matrix across the inner membrane and into the intermembrane space

D

Which of the following statements best describes the primary role played by oxygen in cellular respiration? A) It yields energy in the form of ATP as it is passed down the electron transport chain. B) It oxidizes glucose to form two molecules of pyruvate. C) It serves as an acceptor for carbon, forming CO 2 in the citric acid cycle. D) It serves as the final acceptor for electrons from the electron transport chain.

D