BIO 111 Chapter 9

How many oxygen molecules (O2) are required each time a molecule of glucose (C6H12O6) is completely oxidized to carbon dioxide and water via aerobic respiration,? A) 1 B) 3 C) 6 D) 12 E) 30

6

Which portion of the pathway in Figure 9.1 contains a phosphorylation reaction in which ATP is the phosphate source? A) A B) B C) C D) D E) E

A

Which portion of the pathway in Figure 9.1 involves an endergonic reaction? A) A B) B C) C D) D E) E

A

Which step in Figure 9.1 shows a split of one molecule into two smaller molecules? A) A B) B C) C D) D E) E

B

In which step in Figure 9.1 is an inorganic phosphate added to the reactant? A) A B) B C) C D) D E) E

C

Which step in Figure 9.1 is a redox reaction? A) A B) B C) C D) D E) E

C

What happens at the end of the chain in Figure 9.3? A) 2 electrons combine with a proton and a molecule of NAD+. B) 2 electrons combine with a molecule of oxygen and two hydrogen atoms. C) 4 electrons combine with a molecule of oxygen and 4 protons. D) 4 electrons combine with four hydrogen and two oxygen atoms. E) 1 electron combines with a molecule of oxygen and a hydrogen atom.

4 electrons combine with a molecule of oxygen and 4 protons.

You have a friend who lost 7 kg (about 15 pounds) of fat on a regimen of strict diet and exercise. How did the fat leave her body? A) It was released as CO2 and H2O. B) It was converted to heat and then released. C) It was converted to ATP, which weighs much less than fat. D) It was broken down to amino acids and eliminated from the body. E) It was converted to urine and eliminated from the body.

It was released as CO2 and H2O.

Starting with citrate, which of the following combinations of products would result from three acetyl CoA molecules entering the citric acid cycle (see Figure 9.2)? A) 1 ATP, 2 CO2, 3 NADH, and 1 FADH2 B) 2 ATP, 2 CO2, 3 NADH, and 3 FADH2 C) 3 ATP, 3 CO2, 3 NADH, and 3 FADH2 D) 3 ATP, 6 CO2, 9 NADH, and 3 FADH2 E) 38 ATP, 6 CO2, 3 NADH, and 12 FADH2

3 ATP, 6 CO2, 9 NADH, and 3 FADH2

For each mole of glucose (C6H12O6) oxidized by cellular respiration, how many moles of CO2 are released in the citric acid cycle (see Figure 9.2)? A) 2 B) 4 C) 6 D) 12 E) 3

4

Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle? A) pyruvate B) malate or fumarate C) acetyl CoA D) α-ketoglutarate E) succinyl CoA

acetyl CoA

Which of the following normally occurs regardless of whether or not oxygen (O2) is present? A) glycolysis B) fermentation C) oxidation of pyruvate to acetyl CoA D) citric acid cycle E) oxidative phosphorylation (chemiosmosis)

glycolysis

Which of the following occurs 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 E) oxidative phosphorylation

glycolysis and fermentation

Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water? A) glycolysis B) fermentation C) oxidation of pyruvate to acetyl CoA D) citric acid cycle E) oxidative phosphorylation (chemiosmosis)

oxidative phosphorylation (chemiosmosis)

One function of both alcohol fermentation and lactic acid fermentation is to A) reduce NAD+ to NADH. B) reduce FAD+ to FADH2. C) oxidize NADH to NAD+. D) reduce FADH2 to FAD+. E) do none of the above.

oxidize NADH to NAD+.

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

oxygen.

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

provide the energy that establishes the proton gradient.

In a mitochondrion, if the matrix ATP concentration is high, and the intermembrane space proton concentration is too low to generate sufficient proton-motive force, then A) ATP synthase will increase the rate of ATP synthesis. B) ATP synthase will stop working. C) ATP synthase will hydrolyze ATP and pump protons into the intermembrane space. D) ATP synthase will hydrolyze ATP and pump protons into the matrix.

ATP synthase will hydrolyze ATP and pump protons into the intermembrane space.

After the further agitation of the membrane vesicles, what must be lost from the membrane? A) the ability of NADH to transfer electrons to the first acceptor in the electron transport chain B) the prosthetic groups like heme from the transport system C) cytochromes D) ATP synthase, in whole or in part E) the contact required between inner and outer membrane surfaces

ATP synthase, in whole or in part

Brown fat cells produce a protein called thermogenin in their mitochondrial inner membrane. Thermogenin is a channel for facilitated transport of protons across the membrane. What will occur in the brown fat cells when they produce thermogenin? A) ATP synthesis and heat generation will both increase. B) ATP synthesis will increase, and heat generation will decrease. C) ATP synthesis will decrease, and heat generation will increase. D) ATP synthesis and heat generation will both decrease. E) ATP synthesis and heat generation will stay the same.

ATP synthesis will decrease, and heat generation will increase.

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 oxygen. E) ATP, pyruvate, and acetyl CoA.

ATP, CO2, and ethanol (ethyl alcohol).

Which of the protein complexes labeled with Roman numerals in Figure 9.3 will transfer electrons to O2? A) complex I B) complex II C) complex III D) complex IV E) All of the complexes can transfer electrons to O2.

complex IV

Starting with one molecule of isocitrate and ending with fumarate, how many ATP molecules can be made through substrate-level phosphorylation (see Figure 9.2)? A) 1 B) 2 C) 11 D) 12 E) 24

1

For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle (see Figure 9.2), what is the total number of NADH + FADH2 molecules produced? A) 4 B) 5 C) 6 D) 10 E) 12

12

If a cell is able to synthesize 30 ATP molecules for each molecule of glucose completely oxidized by carbon dioxide and water, how many ATP molecules can the cell synthesize for each molecule of pyruvate oxidized to carbon dioxide and water? A) 0 B) 1 C) 12 D) 14 E) 15

12

Which of the following most accurately describes what is happening along the electron transport chain in Figure 9.3? A) Chemiosmosis is coupled with electron transfer. B) Each electron carrier alternates between being reduced and being oxidized. C) ATP is generated at each step. D) Energy of the electrons increases at each step. E) Molecules in the chain give up some of their potential energy.

Each electron carrier alternates between being reduced and being oxidized.

Which statement best supports the hypothesis that glycolysis is an ancient metabolic pathway that originated before the last universal common ancestor of life on Earth? A) Glycolysis is widespread and is found in the domains Bacteria, Archaea, and Eukarya. B) Glycolysis neither uses nor needs O2. C) Glycolysis is found in all eukaryotic cells. D) The enzymes of glycolysis are found in the cytosol rather than in a membrane-enclosed organelle. E) Ancient prokaryotic cells, the most primitive of cells, made extensive use of glycolysis long before oxygen was present in Earthʹs atmosphere.

Glycolysis is widespread and is found in the domains Bacteria, Archaea, and Eukarya.

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) affinity of oxygen for electrons. D) H+ concentration across the membrane holding ATP synthase. E) transfer of phosphate to ADP.

H+ concentration across the membrane holding ATP synthase.

Why is glycolysis considered to be one of the first metabolic pathways to have evolved? A) It produces much less ATP than does oxidative phosphorylation. B) It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms. C) It is found in prokaryotic cells but not in eukaryotic cells. D) It relies on chemiosmosis, which is a metabolic mechanism present only in the first cellsʹ prokaryotic cells. E) It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells.

It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.

In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve? A) It allows for an increased rate of glycolysis. B) It allows for an increased rate of the citric acid cycle. C) It increases the surface for oxidative phosphorylation. D) It increases the surface for substrate-level phosphorylation. E) It allows the liver cell to have fewer mitochondria.

It increases the surface for oxidative phosphorylation.

Phosphofructokinase is an important control enzyme in the regulation of cellular respiration. Which of the following statements correctly describes phosphofructokinase activity? A) It is inhibited by AMP. B) It is activated by ATP. C) It is activated by citrate, an intermediate of the citric acid cycle. D) It catalyzes the conversion of fructose 1,6-bisphosphate to fructose 6-phosphate, a early step of glycolysis. E) It is an allosteric enzyme.

It is an allosteric enzyme.

When an individual is exercising heavily and when the muscle becomes oxygen-deprived, muscle cells convert pyruvate to lactate. What happens to the lactate in skeletal muscle cells? A) It is converted to NAD+. B) It produces CO2 and water. C) It is taken to the liver and converted back to pyruvate. D) It reduces FADH2 to FAD+. E) It is converted to alcohol.

It is taken to the liver and converted back to pyruvate.

Figure 9.3 shows the electron transport chain. Which of the following is the combination of substances that is initially added to the chain? A) oxygen, carbon dioxide, and water B) NAD+, FAD, and electrons C) NADH, FADH2, and protons D) NADH, FADH2, and O2 E) oxygen and protons

NADH, FADH2, and O2

If pyruvate oxidation is blocked, what will happen to the levels of oxaloacetate and citric acid in the citric acid cycle shown in Figure 9.2? A) There will be no change in the levels of oxaloacetate and citric acid. B) Oxaloacetate will decrease and citric acid will accumulate. C) Oxaloacetate will accumulate and citric acid will decrease. D) Both oxaloacetate and citric acid will decrease. E) Both oxaloacetate and citric acid will accumulate.

Oxaloacetate will accumulate and citric acid will decrease.

A mutation in yeast makes it unable to convert pyruvate to ethanol. How will this mutation affect these yeast cells? A) The mutant yeast will be unable to grow anaerobically. B) The mutant yeast will grow anaerobically only when given glucose. C) The mutant yeast will be unable to metabolize glucose. D) The mutant yeast will die because they cannot regenerate NAD+ from NAD. E) The mutant yeast will metabolize only fatty acids.

The mutant yeast will be unable to grow anaerobically.

When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? A) The pH of the matrix increases. B) ATP synthase pumps protons by active transport. C) The electrons gain free energy. D) The cytochromes phosphorylate ADP to form ATP. E) NAD+ is oxidized.

The pH of the matrix increases.

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. 96) These three steps result in the formation of A) acetyl CoA, O2, and ATP. B) acetyl CoA, FADH2, and CO2. C) acetyl CoA, FAD, H2, and CO2. D) acetyl CoA, NADH, H+, and CO2. E) acetyl CoA, NAD+, ATP, and CO2.

acetyl CoA, NADH, H+, and CO2.

Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes. However, the fragments will reseal ʺinside out.ʺ These little vesicles that result can still transfer electrons from NADH to oxygen and synthesize ATP. If the membranes are agitated further, however, the ability to synthesize ATP is lost. 98) After the first disruption, when electron transfer and ATP synthesis still occur, what must be present? A) all of the electron transport proteins as well as ATP synthase B) all of the electron transport system and the ability to add CoA to acetyl groups C) the ATP synthase system D) the electron transport system E) plasma membranes like those bacteria use for respiration

all of the electron transport proteins as well as ATP synthase

Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in A) all cells, but only in the presence of oxygen. B) only eukaryotic cells, in the presence of oxygen. C) only in mitochondria, using either oxygen or other electron acceptors. D) all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors. E) all cells, in the absence of respiration.

all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors.

High levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in glycolysis. Citric acid binds to the enzyme at a different location from the active site. This is an example of A) competitive inhibition. B) allosteric regulation. C) the specificity of enzymes for their substrates. D) an enzyme requiring a cofactor.

allosteric regulation.

The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of A) active transport. B) an endergonic reaction coupled to an exergonic reaction. C) a reaction with a positive ΔG . D) osmosis. E) allosteric regulation.

an endergonic reaction coupled to an exergonic reaction.

What is the purpose of beta oxidation in respiration? A) oxidation of glucose B) oxidation of pyruvate C) feedback regulation D) control of ATP accumulation E) breakdown of fatty acids

breakdown of fatty acids

When skeletal muscle cells undergo anaerobic respiration, they become fatigued and painful. This is now known to be caused by A) buildup of pyruvate. B) buildup of lactate. C) increase in sodium ions. D) increase in potassium ions. E) increase in ethanol.

buildup of lactate.

During intense exercise, as skeletal muscle cells go into anaerobiosis, the human body will increase its catabolism of A) fats only. B) carbohydrates only. C) proteins only. D) fats, carbohydrates, and proteins. E) fats and proteins only.

carbohydrates only.

When skeletal muscle cells are oxygen-deprived, the heart still pumps. What must the heart muscle cells be able to do? A) derive sufficient energy from fermentation B) continue aerobic metabolism when skeletal muscle cannot C) transform lactate to pyruvate again D) remove lactate from the blood E) remove oxygen from lactate

continue aerobic metabolism when skeletal muscle cannot

What carbon sources can yeast cells metabolize to make ATP from ADP under anaerobic conditions? A) glucose B) ethanol C) pyruvate D) lactic acid E) either ethanol or lactic acid

glucose

Yeast cells that have defective mitochondria incapable of respiration will be able to grow by catabolizing which of the following carbon sources for energy? A) glucose B) proteins C) fatty acids D) glucose, proteins, and fatty acids E) Such yeast cells will not be capable of catabolizing any food molecules, and will therefore die.

glucose

Which metabolic pathway is common to both cellular respiration and fermentation? A) the oxidation of pyruvate to acetyl CoA B) the citric acid cycle C) oxidative phosphorylation D) glycolysis E) chemiosmosis

glycolysis

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) synthesis of acetyl CoA from pyruvate E) reduction of pyruvate to lactate

glycolysis

Which catabolic processes may have been used by cells on ancient Earth before free oxygen became available? A) glycolysis and fermentation only B) glycolysis and the citric acid cycle only C) glycolysis, pyruvate oxidation, and the citric acid cycle D) oxidative phosphorylation only E) glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation, using an electron acceptor other than oxygen

glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation, using an electron acceptor other than oxygen

What is proton-motive force? A) the force required to remove an electron from hydrogen B) the force exerted on a proton by a transmembrane proton concentration gradient C) the force that moves hydrogen into the intermembrane space D) the force that moves hydrogen into the mitochondrion E) the force that moves hydrogen to NAD+

he force exerted on a proton by a transmembrane proton concentration gradient

Even though plants carry on photosynthesis, plant cells still use their mitochondria for oxidation of pyruvate. When and where will this occur? A) in photosynthetic cells in the light, while photosynthesis occurs concurrently B) in nonphotosynthesizing cells only C) in cells that are storing glucose only D) in all cells all the time E) in photosynthesizing cells in the light and in other tissues in the dark

in all cells all the time

In prokaryotes, the respiratory electron transport chain is located A) in the mitochondrial inner membrane. B) in the mitochondrial outer membrane. C) in the plasma membrane. D) in the cytoplasm. E) in the bacterial outer membrane.

in the plasma membrane.

Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount of ATP in a cell would be expected to A) inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle. B) activate the enzyme and thus slow the rates of glycolysis and the citric acid cycle. C) inhibit the enzyme and thus increase the rates of glycolysis and the citric acid cycle. D) activate the enzyme and increase the rates of glycolysis and the citric acid cycle. E) inhibit the enzyme and thus increase the rate of glycolysis and the concentration of citrate.

inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle.

Where is ATP synthase located in the mitochondrion? A) cytosol B) electron transport chain C) outer membrane D) inner membrane E) mitochondrial matrix

inner membrane

An organism is discovered that thrives both in the presence and absence of oxygen in the air. Curiously, the consumption of sugar increases as oxygen is removed from the organismʹs environment, even though the organism does not gain much weight. This organism A) must use a molecule other than oxygen to accept electrons from the electron transport chain. B) is a normal eukaryotic organism. C) is photosynthetic. D) is an anaerobic organism. E) is a facultative anaerobe.

is a facultative anaerobe.

It is possible to prepare vesicles from portions of the inner mitochondrial membrane. Which one of the following processes could still be carried on by this isolated inner membrane? A) the citric acid cycle B) oxidative phosphorylation C) glycolysis and fermentation D) reduction of NAD+ E) both the citric acid cycle and oxidative phosphorylation

oxidative phosphorylation

What is the oxidizing agent in the following reaction? Pyruvate + NADH + H+ → Lactate + NAD+ A) oxygen B) NADH C) NAD+ D) lactate E) pyruvate

pyruvate

In alcohol fermentation, NAD+ is regenerated from NADH by A) reduction of acetaldehyde to ethanol (ethyl alcohol). B) oxidation of pyruvate to acetyl CoA. C) reduction of pyruvate to form lactate. D) oxidation of ethanol to acetyl CoA. E) reduction of ethanol to pyruvate.

reduction of acetaldehyde to ethanol (ethyl alcohol).

The ATP made during fermentation is generated by which of the following? A) the electron transport chain B) substrate-level phosphorylation C) chemiosmosis D) oxidative phosphorylation E) aerobic respiration

substrate-level phosphorylation

Most CO2 from catabolism is released during A) glycolysis. B) the citric acid cycle. C) lactate fermentation. D) electron transport. E) oxidative phosphorylation.

the citric acid cycle.

Why is coenzyme A, a sulfur-containing molecule derived from a B vitamin, added? A) because sulfur is needed for the molecule to enter the mitochondrion B) in order to utilize this portion of a B vitamin which would otherwise be a waste product from another pathway C) to provide a relatively unstable molecule whose acetyl portion can be readily transferred to a compound in the citric acid cycle D) because it drives the reaction that regenerates NAD+ E) in order to remove one molecule of CO2

to provide a relatively unstable molecule whose acetyl portion can be readily transferred to a compound in the citric acid cycle

In vertebrate animals, brown fat tissueʹs color is due to abundant blood vessels and capillaries. White fat tissue, on the other hand, is specialized for fat storage and contains relatively few blood vessels or capillaries. Brown fat cells have a specialized protein that dissipates the proton-motive force across the mitochondrial membranes. Which of the following might be the function of the brown fat tissue? A) to increase the rate of oxidative phosphorylation from its few mitochondria B) to allow the animals to regulate their metabolic rate when it is especially hot C) to increase the production of ATP D) to allow other membranes of the cell to perform mitochondrial functions E) to regulate temperature by converting most of the energy from NADH oxidation to heat

to regulate temperature by converting most of the energy from NADH oxidation to heat

These inside-out membrane vesicles A) will become acidic inside the vesicles when NADH is added. B) will become alkaline inside the vesicles when NADH is added. C) will make ATP from ADP and i if transferred to a pH 4 buffered solution after incubation in a pH 7 buffered solution. D) will hydrolyze ATP to pump protons out of the interior of the vesicle to the exterior. E) will reverse electron flow to generate NADH from NAD+ in the absence of oxygen.

will become acidic inside the vesicles when NADH is added.

Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the citric acid cycle. Which intermediate would supply the carbon skeleton for synthesis of a five-carbon amino acid (see Figure 9.2)? A) succinate B) malate C) citrate D) α-ketoglutarate E) isocitrate

α-ketoglutarate