Exam 2 Chapter 7 (Practice Questions)

Front 1

The breakdown (hydrolysis) of ATP, which yields ADP and an inorganic phosphate ion, is an exergonic reaction yielding approximately ________ kcal of free energy per mole ofATP under biological conditions.

Back 1

-12

Front 2

Part of the unusually large amount of free encergy that results from the hydrolysis of ATP derives from the large number of ________ charges near each other on neighboringphosphate groups.

Back 2

?????

Front 3

Oxidation and ________ occur together.

Back 3

Reduction

Front 4

Thanks to its ability to carry electrons and free energy, ________ is the major anduniversal energy intermediary in cells.

Back 4

NAD

Front 5

Pyruvate is ________ to form acetate.

Back 5

Oxidized

Front 6

The chemiosmotic formation of ATP during the operation of the respiratory chain is called ________.

Back 6

Oxidative Phosphorylation

Front 7

The loss of an electron by a ferrous ion (Fe2+) to give a ferric ion (Fe3+) is called________.

Back 7

Oxidation

Front 8

In a redox reaction, the reactant that becomes oxidized is called a ________.

Back 8

Electron, Carbon, Enzyme?

Front 9

A chemical reaction resulting in the transfer of electrons or hydrogen atoms is called a________ reaction.

Back 9

Redox

Front 10

The pathway for the oxidation of glucose to pyruvate is called ________.

Back 10

Citric Acid Cycle

Front 11

The conversion of glucose to lactic acid is a form of ________.

Back 11

Fermentation

Front 12

Fatty acids must be converted to ________ before they can be used for respiratory ATP production.

Back 12

Acetate

Front 13

During alcoholic fermentation, NAD+ is regenerated by the reduction of acetaldehyde to________.

Back 13

Ethanol

Front 14

NAD is an abbreviation for ________.

Back 14

Nicotinamide adenine dinucleotide

Front 15

An enzyme that transfers phosphorous from ATP to another protein is called a ________.

Back 15

Kinase

Front 16

The earliest forms of life probably used ________ to generate ATP.

Back 16

fermentation, glycolysis?????

Front 17

ATP is A) a short-term, energy-storage compound. B) the cell's principle compound for energy transfers. C) synthesized within mitochondria. D) the molecule all living cells rely on to do work. E) All of the above

Back 17

E

Front 18

When a molecule loses hydrogen atoms (not hydrogen ions), it becomes A) reduced. B) oxidized. C) redoxed. D) hydrogenated. E) hydrolyzed.

Back 18

B

Front 19

Use the following to answer question 19:

In the diagram shown above, Reaction 1 is __________, and Reaction 2 is __________. A) oxidation, oxidation B) oxidation, reduction C) reduction, reduction D) reduction, oxidation E) oxiduction, oxiduction

Back 19

??????

Front 20

The end product of glycolysis is A) pyruvate. B) the starting point for the citric acid cycle. C) the starting point for the fermentation pathway. D) a and b E) a, b, and c

Back 20

E

Front 21

The ΔG of glucose oxidation is __________ kcal/mol. A) close to 686 B) ñ686 C) 53 D) ñ53 E) ñ12

Back 21

B

Front 22

In the conversion of succinate to fumarate, hydrogen atoms are transferred to FAD. Theconversion of succinate and FAD to fumarate and FADH2 is an example of A) hydrolysis. B) an allosteric reaction. C) a metabolic pathway. D) an aerobic reaction. E) a redox reaction.

Back 22

E

Front 23

The oxidation of malate to oxaloacetate is coupled to the reduction of NAD+ to NADH +H+. NAD+ is a(n) A) reducing agent. B) oxidizing agent. C) vitamin. D) phosphate ester. E) phosphorylating agent.

Back 23

B

Front 24

During respiration, NADH donates two electrons to ubiquinone. When this happens,ubiquinone is A) reduced. B) oxidized. C) phosphorylated. D) aerobic. E) hydrolyzed.

Back 24

A

Front 25

Which of the following oxidizes other compounds by gaining free energy and hydrogen atoms and reduces other compounds by giving up free energy and hydrogen atoms? A) Vitamins B) Adenine C) ATP D) NAD E) Riboflavin

Back 25

D

Front 26

Isocitrate dehydrogenase is an enzyme of the citric acid cycle. Where in the cell is this enzyme located? A) In the thylakoids B) In the cytoplasm C) In the chloroplast D) In the mitochondrial matrix E) In the plasma membrane

Back 26

Mitochondria

Front 27

In the first reaction of glycolysis, glucose receives a phosphate group from ATP. Thisreaction is A) respiration. B) a redox reaction. C) exergonic. D) endergonic. E) fermentation.

Back 27

D

Front 28

The reduction of pyruvate to lactic acid during fermentation allows glycolysis to continuein the absence of oxygen. Why? A) Water is formed during this reaction. B) This reaction is a kinase reaction. C) This reaction is coupled to the oxidation of NADH to NAD+. D) This reaction is coupled to the formation of ATP. E) This reaction is coupled to the reduction of NAD+ to NADH.

Back 28

C

Front 29

During glycolysis, for each mole of glucose oxidized to pyruvate A) 6 moles of ATP are produced. B) 4 moles of ATP are used, and 2 moles of ATP are produced. C) 2 moles of ATP are used, and 4 moles of ATP are produced. D) 2 moles of NAD+ are produced. E) no ATP is produced.

Back 29

C

Front 30

In steps 6 through 10 of glycolysis, the conversion of one mole of glyceraldehyde 3-phosphate to pyruvate yields 2 moles of ATP. But the oxidation of glucose to pyruvate produces a total of 4 moles of ATP. Where do the remaining 2 moles of ATP come from? A) One mole of glucose gives 2 moles of glyceraldehyde 3-phosphate. B) Two moles of ATP are used during the conversion of glucose to glyceraldehyde 3-phosphate. C) Glycolysis produces 2 moles of NADH. D) Fermentation of pyruvate to lactic acid yields 2 moles of ATP. E) Fermentation of pyruvate to lactic acid yields 2 moles of NAD+.

Back 30

A

Front 31

For glycolysis to continue, all cells require A) a respiratory chain. B) oxygen. C) mitochondria. D) chloroplasts. E) NAD+.

Back 31

E

Front 32

The free energy released during the oxidation of glyceraldehyde 3-phosphate to 1,3bisphosphoglycerate is A) used to oxidize NADH. B) lost as heat. C) used to synthesize ATP. D) used to reduce NAD+. E) stored in lactic acid.

Back 32

D

Front 33

The oxidation of pyruvate to carbon dioxide is called A) fermentation. B) the citric acid cycle. C) glycolysis. D) oxidative phosphorylation. E) the respiratory chain.

Back 33

B

Front 34

During the energy-priming portion of glycolysis, the phosphates from ATP molecules are A) added to the first and sixth carbons. B) added to the second and fourth carbons. C) wasted, as an energy investment. D) used to make pyruvate. E) used to make lactate.

Back 34

A

Front 35

Which of the following is produced during the citric acid cycle? A) FAD B) Pyruvate C) Reduced electron carriers D) Lactic acid E) Water

Back 35

C

Front 36

Some of the free energyreleased by oxidation of pyruvate to acetate is stored in acetyl CoA. How doesacetyl CoA store free energy? A) Acetyl CoA has a higher free energy thanacetate. B) Acetyl CoA is an electron carrier. C) Acetyl CoA is a phosphate donor. D) Acetate + CoA Æ acetyl CoA is an exergonicreaction. E) Reduction of acetyl CoA is coupled to ATPsynthesis.

Back 36

A

Front 37

The oxidizing agent at the end of the respiratory chain is A) O2. B) NAD+. C) ATP. D) FAD. E) ubiquinone.

Back 37

A

Front 38

During the citric acid cycle, energy stored in acetyl CoA is used to A) create a proton gradient. B) drive the reaction ADP + Pi ñ ATP. C) reduce NAD+ to NADH. D) drive the reaction oxaloacetate Æ citric acid. E) reduce FAD to FADH2.

Back 38

D

Front 39

During the citric acid cycle, oxidative steps are coupled to A) oxidative phosphorylation. B) the oxidation of water. C) the oxidation of electron carriers. D) the hydrolysis of ATP. E) the reduction of electron carriers.

Back 39

E

Front 40

Animals breathe in air containing oxygen and breathe out air with less oxygen and morecarbon dioxide. The carbon dioxide comes from A) the carbon from hydrocarbons and the oxygen from the air. B) the citric acid cycle. C) glycolysis. D) waste products. E) All of the above

Back 40

B

Front 41

The drug 2,4-dinitrophenol (DNP) destroys the proton gradient across the innermitochondrial membrane. What would you expect to be the effect of incubating isolated mitochondria in a solution of DNP? A) Oxygen would no longer be reduced to water. B) No ATP would be made during transport of electrons down the respiratory chain. C) Mitochondria would show a burst of increased ATP synthesis. D) Glycolysis would stop. E) Mitochondria would switch from glycolysis to fermentation.

Back 41

B

Front 42

Electron transport within NADH-Q reductase, cytochrome reductase, and cytochrome oxidase can be coupled to proton transport from the mitochondrial matrix to the space between the inner and outer mitochondrial membranes because those protein complexesare located A) in the mitochondrial matrix. B) within the inner mitochondrial membrane. C) in the space between the inner and outer mitochondrial membranes. D) in the cytoplasm. E) loosely attached to the inner mitochondrial membrane.

Back 42

B

Front 43

According to the chemiosmotic theory, the energy for the synthesis of ATP during theflow of electrons down the respiratory chain is provided directly by the A) hydrolysis of GTP. B) reduction of NAD+. C) diffusion of protons. D) reduction of FAD. E) hydrolysis of ATP.

Back 43

C

Front 44

In the absence of oxygen, cells capable of fermentation A) accumulate glucose. B) no longer produce ATP. C) accumulate pyruvate. D) oxidize FAD. E) oxidize NADH to produce NAD+.

Back 44

E

Front 45

For bacteria to continue growing rapidly when they are shifted from an environmentcontaining oxygen to an anaerobic environment, they must A) increase the rate of the citric acid cycle. B) produce more ATP per mole of glucose during glycolysis. C) produce ATP during the oxidation of NADH. D) increase the rate of transport of electrons down the respiratory chain. E) increase the rate of the glycolytic reactions.

Back 45

E

Front 46

In alcoholic fermentation, NAD+ is produced during the A) oxidation of pyruvate to acetyl CoA. B) reduction of pyruvate to lactic acid. C) reduction of acetaldehyde to ethanol. D) hydrolysis of ATP to ADP. E) oxidation of glucose.

Back 46

C

Front 47

During the fermentation of 1 molecule of glucose, the net production of ATP is A) 1 molecule. B) 2 molecules. C) 3 molecules. D) 6 molecules. E) 8 molecules.

Back 47

B

Front 48

The portion of aerobic respiration that produces the most ATP per mole of glucose is A) oxidative phosphorylation. B) the citric acid cycle. C) glycolysis. D) lactic acid fermentation. E) alcoholic fermentation.

Back 48

C

Front 49

More free energy is released during the citric acid cycle than during glycolysis, but only 1 mole of ATP is produced for each mole of acetyl CoA that enters the cycle. What happens to most of the remaining free energy that is produced during the citric acidcycle? A) It is used to synthesize GTP. B) It is used to reduce electron carriers. C) It is lost as heat. D) It is used to reduce pyruvate. E) It is converted to kinetic energy.

Back 49

B

Front 50

Animals inhale air-containing oxygen and exhale air with less oxygen and more carbondioxide. Later, the oxygen from the air will mostly be found in A) the carbon dioxide that is exhaled. B) water. C) organic molecules. D) ethanol. E) lactate.

Back 50

B

Front 51

When the supply of acetyl CoA being produced exceeds the demands of the citric acidcycle, some of the acetyl CoA is diverted to the synthesis of A) pyruvate. B) NAD. C) proteins. D) fatty acids. E) lactic acid.

Back 51

D

Front 52

The site of oxygen utilization is the A) nucleus. B) chloroplasts. C) endoplasmic reticulum. D) mitochondria. E) cytosol.

Back 52

D

Front 53

Before starch can be used for respiratory ATP production, it must be hydrolyzed to A) pyruvate. B) fatty acids. C) amino acids. D) glucose. E) oxaloacetate.

Back 53

D

Front 54

When yeast cells are switched from aerobic to anaerobic growth conditions, the rate of glycolysis increases. The rate of glycolysis is regulated by the concentration of__________ in the cell. A) ATP B) acetyl CoA C) oxaloacetate D) FAD E) protein

Back 54

A

Front 55

When acetyl CoA builds up in the cell, it increases the activity of the enzyme thatsynthesizes oxaloacetate from pyruvate and carbon dioxide. Acetyl CoA is acting as a(n) A) electron carrier. B) substrate. C) allosteric activator. D) acetate donor. E) proton pump.

Back 55

C

Front 56

In yeast, if the citric acid cycle is shut down because of a lack of oxygen, glycolysis willprobably A) shut down. B) increase. C) produce more ATP per mole of glucose. D) produce more NADH per mole of glucose. E) produce acetyl CoA for fatty acid synthesis.

Back 56

B

Front 57

The function of NAD+ is to A) cause the release of energy to adjacent cells when energy is needed in aerobicconditions. B) hasten the release of energy when the cell has been deprived of oxygen. C) carry hydrogen atoms and free energy from compounds being oxidized and to givehydrogen atoms and free energy to compounds being reduced. D) block the release of energy to adjacent cells. E) None of the above

Back 57

C

Front 58

The end result of glycolysis is that A) 38 ATP molecules are created. B) 8 NAD molecules get reduced. C) 2 molecules of pyruvate are formed. D) 1 molecule of glucose is converted to lactic acid. E) None of the above

Back 58

C

Front 59

The results of the first five reactions of the glycolytic pathway are A) adding phosphates, modifying sugars, and forming G3P. B) oxidative steps, proton pumping, and reactions with oxygen. C) oxidation of pyruvate and formation of acetyl CoA. D) removal of hydrogen and protons from glucose. E) None of the above

Back 59

A

Front 60

For the citric acid cycle to proceed, it is necessary for A) pyruvate to bind to oxaloacetate. B) carbon dioxide to bind to oxaloacetate. C) an acetyl group to bind to oxaloacetate. D) water to be oxidized. E) None of the above

Back 60

C

Front 61

Which of the following events occurs in the respiratory chain? A) Carbon dioxide is released. B) Carbon dioxide is reduced. C) Cytochromes, FADH, and NADH are oxidized. D) Only NAD+ is reduced. E) None of the above

Back 61

C

Front 62

The respiratory chain contains three large enzymes: NADH-Q reductase, cytochrome reductase, and cyto-chrome oxidase. The function of these enzymes is to A) allow electrons to be transported. B) ensure the production of water and oxygen. C) regulate the passage of water through the chain. D) oxidize NADH. E) None of the above

Back 62

A?????????

Front 63

Oxygen is used by A) glycolysis. B) the citric acid cycle. C) the electron transport chain. D) substrate level phosphorylation. E) ATP sythase.

Back 63

C

Front 64

Pyruvate oxidation generates A) acetate. B) NADH + H+ from NAD+. C) a change in free energy. D) a capture of energy. E) All of the above

Back 64

E

Front 65

Water is a by-product of cellular respiration. The water is produced as a result of A) combining carbon dioxide with protons. B) the conversion of pyruvate to acetyl CoA. C) the degradation of glucose to pyruvate. D) the reduction of oxygen at the end of the electron transport chain. E) None of the above

Back 65

D

Front 66

The formation of ethanol from pyruvate is an example of A) an exergonic reaction. B) providing an extra source of energy from glycolysis. C) a fermentation process that takes place in the absence of oxygen. D) cellular respiration. E) None of the above

Back 66

C

Front 67

Regardless of the electron or hydrogen acceptor employed, fermentation always produces A) AMP. B) DNA. C) Pi. D) NAD+. E) None of the above

Back 67

D

Front 68

Yeast cells tend to create anaerobic conditions because they use oxygen faster than it can be replaced by diffusion through the cell membrane. For this reason, yeast cells A) exhibit a red pigment. B) exhibit a green pigment. C) die. D) produce ethanol. E) None of the above

Back 68

D

Front 69

In human cells (muscle cells), the fermentation process produces A) lactic acid. B) 12 moles of ATP. C) pyruvic acid. D) an excessive amount of energy. E) None of the above

Back 69

A

Front 70

If a cell has an abundant supply of ATP, acetyl CoA may be used A) to enhance fermentation. B) to enhance oxidative metabolism. C) for fatty acid synthesis. D) to convert glucose to glycogen. E) None of the above

Back 70

C

Front 71

In order for glucose to be used as an energy source, it is necessary that A) glucose be formed from fructose. B) glucose phosphate be formed from fructose phosphate. C) glucose be degraded to carbon dioxide. D) 2 ATP molecules be invested in the system. E) None of the above

Back 71

D

Front 72

Many species derive their energy from fermentation. The function of fermentation is to A) reduce NAD+. B) oxidize carbon dioxide. C) oxidize NADH + H+, ensuring a continued supply of ATP. D) produce acetyl CoA. E) None of the above

Back 72

C

Front 73

Proteins must be consumed to provide energy to the brain when glucose and starch stores are depleted because A) the brain must have glucose. B) fatty acids cannot get to the brain. C) amino acids are needed for gluconeogenesis. D) All of the above E) None of the above

Back 73

?

Front 74

The chemiosmotic generation of ATP is driven by A) osmotic movement of water into an area of high solute concentration. B) the addition of protons to ADP and phosphate via enzymes. C) oxidative phosphorylation. D) a difference in H+ concentration of both sides of a membrane. E) None of the above

Back 74

D

Front 75

When a cell needs energy, cellular respiration is regulated by the citric acid cycle enzymeisocitrate dehydrogenase, which is stimulated by A) H+. B) heat. C) oxygen. D) ADP. E) None of the above

Back 75

D

Front 76

Substrate-level phosphorylation is transfer of A) a phosphate to a protein. B) a phosphate to a substrate. C) a phosphate to an ADP. D) an ATP to a protein. E) a phosphate from ATP to a substrate.

Back 76

C

Front 77

The proton-motive force is A) the force a proton has on the motive. B) the proton concentration gradient and electric charge difference. C) a metabolic pathway. D) ATP synthase. E) a redox reaction.

Back 77

B

Front 78

Most ATP made in our bodies is made A) by glycolysis. B) in the citric acid cycle. C) using ATP synthase. D) from photosynthesis. E) burning fat.

Back 78

C

Front 79

Brown fat is "burned" to raise the body temperature of some small mammals by A) thermogenin uncoupling respiration. B) increasing the rate of glycolysis. C) shivering. D) hydrogen ions leaking across the cell's plasma membrane. E) cytochrome reductase.

Back 79

?

Front 80

In eukaryotic cells, some glycolytic enzymes are found to be associated with the A) mitochondrial membrane. B) mitochondrial matrix. C) nucleus. D) cytoskeleton. E) None of the above

Back 80

?