Question 1

Fermentation is a process that occurs

Accepted Answer

A)  in muscle tissue when there is an insufficient supply of oxygen. 
B)  only in microorganisms. 
C)  in the mitochondrion. 
D)  in the absence of both NAD+ and NADH. 
E)  in response to high levels of oxygen. 
A)  in muscle tissue when there is an insufficient supply of oxygen. 
B)  only in microorganisms. 
C)  in the mitochondrion. 
D)  in the absence of both NAD+ and NADH. 
E)  in response to high levels of oxygen. A

Question 2

Refer to the diagram below, showing energy-releasing metabolic pathways.   Explain what happens to this sequence of pathways in the absence of O2.

Accepted Answer

Pyruvate undergoes fermentation to form lactic acid or alcohol rather than continuing to step 2.

Question 3

Fermentation

Accepted Answer

A)  results in the formation of either lactic acid or ethanol. 
B)  completely oxidizes glucose to CO2 and H2O. 
C)  does not involve substrate-level ADP synthesis. 
D)  occurs under aerobic conditions in yeasts. 
E)  is endergonic. 
A)  results in the formation of either lactic acid or ethanol. 
B)  completely oxidizes glucose to CO2 and H2O. 
C)  does not involve substrate-level ADP synthesis. 
D)  occurs under aerobic conditions in yeasts. 
E)  is endergonic. A

Question 4

The oxidizing agent at the end of the electron transport chain is

Accepted Answer

A)  O2. 
B)  NAD+. 
C)  ATP. 
D)  FAD. 
E)  ubiquinone. 
A)  O2. 
B)  NAD+. 
C)  ATP. 
D)  FAD. 
E)  ubiquinone.

Question 5

Approximately how many ATP molecules per glucose molecule are produced via glycolysis and cellular respiration?

Accepted Answer

A)  2 
B)  4 
C)  8 
D)  16 
E)  32 
A)  2 
B)  4 
C)  8 
D)  16 
E)  32

Question 6

The main control point of glycolysis is the glycolytic enzyme

Accepted Answer

A)  phosphofructokinase. 
B)  acetylfructokinase. 
C)  oxaloacetate convertase. 
D)  isocitrate dehydrogenase. 
E)  kinase. 
A)  phosphofructokinase. 
B)  acetylfructokinase. 
C)  oxaloacetate convertase. 
D)  isocitrate dehydrogenase. 
E)  kinase.

Question 7

Methanogens are bacteria that carry out a form of cellular respiration under anaerobic conditions inside the ruminant organs of cows and sheep.They take in carbon dioxide and release methane.In these organisms, carbon dioxide acts in place of oxygen as an alternative _______.

Accepted Answer

The answer of Methanogens are bacteria that carry out a...

Question 8

More free energy is harvested 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.Most of the remaining free energy released during the citric acid cycle is

Accepted Answer

A)  used to synthesize GTP. 
B)  used to reduce electron carriers. 
C)  lost as heat. 
D)  used to reduce pyruvate. 
E)  converted to kinetic energy. 
A)  used to synthesize GTP. 
B)  used to reduce electron carriers. 
C)  lost as heat. 
D)  used to reduce pyruvate. 
E)  converted to kinetic energy.

Question 9

According to the chemiosmotic theory, the energy for the synthesis of ATP during the flow of electrons down the respiratory chain is provided directly by the

Accepted Answer

A)  hydrolysis of GTP. 
B)  reduction of NAD+. 
C)  hydrolysis of ATP. 
D)  reduction of FAD. 
E)  diffusion of protons. 
A)  hydrolysis of GTP. 
B)  reduction of NAD+. 
C)  hydrolysis of ATP. 
D)  reduction of FAD. 
E)  diffusion of protons.

Question 10

Aerobic organisms exchange air containing O2 with air containing less O2 and more CO2.The CO2 comes from

Accepted Answer

A)  hydrocarbons and the air. 
B)  the citric acid cycle. 
C)  glycolysis. 
D)  waste products. 
E)  oxidative phosphorylation. 
A)  hydrocarbons and the air. 
B)  the citric acid cycle. 
C)  glycolysis. 
D)  waste products. 
E)  oxidative phosphorylation.

Question 11

The carbon-containing molecule that enters glycolysis differs from the one that enters the citric acid cycle.How do the numbers of carbon atoms per molecule compare in these two cases?

Accepted Answer

A)  A six-carbon molecule enters glycolysis, while a four-carbon molecule enters the citric acid cycle. 
B)  A six-carbon molecule enters glycolysis, while a three-carbon molecule enters the citric acid cycle. 
C)  A six-carbon molecule enters glycolysis, while a two-carbon molecule enters the citric acid cycle. 
D)  A four-carbon molecule enters glycolysis, while a three-carbon molecule enters the citric acid cycle. 
E)  A four-carbon molecule enters glycolysis, while a two-carbon molecule enters the citric acid cycle. 
A)  A six-carbon molecule enters glycolysis, while a four-carbon molecule enters the citric acid cycle. 
B)  A six-carbon molecule enters glycolysis, while a three-carbon molecule enters the citric acid cycle. 
C)  A six-carbon molecule enters glycolysis, while a two-carbon molecule enters the citric acid cycle. 
D)  A four-carbon molecule enters glycolysis, while a three-carbon molecule enters the citric acid cycle. 
E)  A four-carbon molecule enters glycolysis, while a two-carbon molecule enters the citric acid cycle.

Question 12

Refer to the table below, showing data collected from experiments using purified soybean mitochondria incubated in buffer containing compound X, compound Y, or no additions.Three different assays were performed on each group of mitochondria to determine the rate of oxygen uptake, ATP synthesis, and formation of a hydrogen ion gradient.The results are expressed as a percentage relative to the control group.   Which conclusion is consistent with these results?

Accepted Answer

A)  Compound X and compound Y inhibit different proteins in the respiratory chain. 
B)  Compound X and compound Y both uncouple electron transport from ATP synthesis. 
C)  Compound X uncouples electron transport from ATP synthesis, and compound Y inhibits a protein in the respiratory chain. 
D)  Compound X inhibits a protein in the respiratory chain, and compound Y uncouples electron transport from ATP synthesis. 
E)  Compound X prevents oxygen from functioning as the final electron acceptor, and compound Y inhibits a protein in the respiratory chain. 
A)  Compound X and compound Y inhibit different proteins in the respiratory chain. 
B)  Compound X and compound Y both uncouple electron transport from ATP synthesis. 
C)  Compound X uncouples electron transport from ATP synthesis, and compound Y inhibits a protein in the respiratory chain. 
D)  Compound X inhibits a protein in the respiratory chain, and compound Y uncouples electron transport from ATP synthesis. 
E)  Compound X prevents oxygen from functioning as the final electron acceptor, and compound Y inhibits a protein in the respiratory chain.

Question 13

In the complete oxidation of glucose, six CO2 molecules are formed per glucose molecule.The number of CO2 molecules released by glycolysis is _______, by pyruvate oxidation is _______, and by the citric acid cycle is _______.

Accepted Answer

A)  zero; zero; six 
B)  zero; two; four 
C)  one; one; four 
D)  one; two; three 
E)  two; two; two 
A)  zero; zero; six 
B)  zero; two; four 
C)  one; one; four 
D)  one; two; three 
E)  two; two; two

Question 14

Refer to the figure below.   Five statements about energy metabolism in cells are given.Which statement can be used to explain the importance of the process shown in the figure?

Accepted Answer

A)  Oxidation of molecules from glucose is coupled to reduction of oxygen, which allows for controlled release of energy in a form that the cell can use. 
B)  The free energy of electron transport is coupled to ATP synthesis using a proton concentration gradient. 
C)  Under anaerobic conditions, NAD+ is regenerated for continued use in glycolysis by either lactic acid or alcoholic fermentation reactions. 
D)  ATP produced by exergonic reactions supplies the free energy needed to drive many endergonic reactions in the cell. 
E)  Anabolic and catabolic metabolic pathways are regulated, usually at the first committed step of each pathway. 
A)  Oxidation of molecules from glucose is coupled to reduction of oxygen, which allows for controlled release of energy in a form that the cell can use. 
B)  The free energy of electron transport is coupled to ATP synthesis using a proton concentration gradient. 
C)  Under anaerobic conditions, NAD+ is regenerated for continued use in glycolysis by either lactic acid or alcoholic fermentation reactions. 
D)  ATP produced by exergonic reactions supplies the free energy needed to drive many endergonic reactions in the cell. 
E)  Anabolic and catabolic metabolic pathways are regulated, usually at the first committed step of each pathway.

Question 15

What is the cellular location of the citric acid cycle?

Accepted Answer

A)  Cell membrane 
B)  Cytosol 
C)  Mitochondrial matrix 
D)  Nucleus 
E)  Lysosome 
A)  Cell membrane 
B)  Cytosol 
C)  Mitochondrial matrix 
D)  Nucleus 
E)  Lysosome

Question 16

Refer to the equation below, summarizing a step in lactic acid fermentation. Pyruvate + NADH + H+ F1F1F1S1F1F1F10 lactate + NAD+
In this reaction, which compound is oxidized and which is reduced?

Accepted Answer

A)  Pyruvate is oxidized and lactate is reduced. 
B)  NADH is oxidized and lactate is reduced. 
C)  Pyruvate is reduced and NADH is oxidized. 
D)  NAD+ is reduced and pyruvate is oxidized. 
E)  Lactate is oxidized and NADH is reduced. 
A)  Pyruvate is oxidized and lactate is reduced. 
B)  NADH is oxidized and lactate is reduced. 
C)  Pyruvate is reduced and NADH is oxidized. 
D)  NAD+ is reduced and pyruvate is oxidized. 
E)  Lactate is oxidized and NADH is reduced.

Question 17

The compound 2,4-dinitrophenol (DNP) is a lipid soluble compound that has been used as a weight loss agent.It functions this way by causing the inner mitochondrial membrane to become leaky with respect to protons.Which result might be expected if cells treated with DNP were examined in detail?

Accepted Answer

A)  The rate of oxygen consumption would be slower in these cells than in untreated cells. 
B)  The ratio of ATP produced to glucose oxidized would be greater in these cells than in untreated cells. 
C)  Electron transport in these cells would be completely blocked. 
D)  ATP production would be slower in these cells than in untreated cells. 
E)  The pH difference across the mitochondrial inner membrane would be greater in these cells than in untreated cells. 
A)  The rate of oxygen consumption would be slower in these cells than in untreated cells. 
B)  The ratio of ATP produced to glucose oxidized would be greater in these cells than in untreated cells. 
C)  Electron transport in these cells would be completely blocked. 
D)  ATP production would be slower in these cells than in untreated cells. 
E)  The pH difference across the mitochondrial inner membrane would be greater in these cells than in untreated cells.

Question 18

Refer to the graph below, containing data from three assays carried out simultaneously on a population of bacterial cells growing in culture.At various points in time, small samples of cells were taken from the population to measure cell number, total protein mass, and mass of enzymes involved in arginine biosynthesis.Halfway through the experiment, arginine was added to the medium in which the population was growing.A vertical arrow is shown on the graph to indicate this time.   What do these data indicate about a mechanism of regulation of arginine biosynthesis in bacterial cells in response to high levels of available arginine?

Accepted Answer

A)  High levels of arginine stimulate a positive feedback regulatory mechanism. 
B)  High levels of arginine stimulate a negative feedback regulatory mechanism. 
C)  High levels of arginine stimulate an inhibition of gene expression. 
D)  High levels of arginine stimulate an activation of enzyme covalent modification. 
E)  High levels of arginine stimulate allosteric inhibition of arginine biosynthesis. 
A)  High levels of arginine stimulate a positive feedback regulatory mechanism. 
B)  High levels of arginine stimulate a negative feedback regulatory mechanism. 
C)  High levels of arginine stimulate an inhibition of gene expression. 
D)  High levels of arginine stimulate an activation of enzyme covalent modification. 
E)  High levels of arginine stimulate allosteric inhibition of arginine biosynthesis.

Question 19

The first and third reactions of the glycolytic pathway result in consumption of ATP.These are examples of

Accepted Answer

A)  endergonic reactions. 
B)  allosteric reactions. 
C)  metabolic pathways. 
D)  oxidation reactions. 
E)  redox reactions. 
A)  endergonic reactions. 
B)  allosteric reactions. 
C)  metabolic pathways. 
D)  oxidation reactions. 
E)  redox reactions.

Question 20

In lactate fermentation, NAD+ is produced during the

Accepted Answer

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. 
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.

Exam 9: Pathways That Harvest Chemical Energy

Fermentation is a process that occurs

Refer to the diagram below, showing energy-releasing metabolic pathways. Explain what happens to this sequence of pathways in the absence of O2.

Fermentation

The oxidizing agent at the end of the electron transport chain is

Approximately how many ATP molecules per glucose molecule are produced via glycolysis and cellular respiration?

The main control point of glycolysis is the glycolytic enzyme

Methanogens are bacteria that carry out a form of cellular respiration under anaerobic conditions inside the ruminant organs of cows and sheep.They take in carbon dioxide and release methane.In these organisms, carbon dioxide acts in place of oxygen as an alternative _______.

More free energy is harvested 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.Most of the remaining free energy released during the citric acid cycle is

According to the chemiosmotic theory, the energy for the synthesis of ATP during the flow of electrons down the respiratory chain is provided directly by the

Aerobic organisms exchange air containing O2 with air containing less O2 and more CO2.The CO2 comes from

The carbon-containing molecule that enters glycolysis differs from the one that enters the citric acid cycle.How do the numbers of carbon atoms per molecule compare in these two cases?

In the complete oxidation of glucose, six CO2 molecules are formed per glucose molecule.The number of CO2 molecules released by glycolysis is _______, by pyruvate oxidation is _______, and by the citric acid cycle is _______.

Refer to the figure below. Five statements about energy metabolism in cells are given.Which statement can be used to explain the importance of the process shown in the figure?

What is the cellular location of the citric acid cycle?

Refer to the equation below, summarizing a step in lactic acid fermentation. Pyruvate + NADH + H+  lactate + NAD+ In this reaction, which compound is oxidized and which is reduced?

The compound 2,4-dinitrophenol (DNP) is a lipid soluble compound that has been used as a weight loss agent.It functions this way by causing the inner mitochondrial membrane to become leaky with respect to protons.Which result might be expected if cells treated with DNP were examined in detail?

The first and third reactions of the glycolytic pathway result in consumption of ATP.These are examples of

In lactate fermentation, NAD+ is produced during the

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Refer to the diagram below, showing energy-releasing metabolic pathways. Explain what happens to this sequence of pathways in the absence of O₂.

Aerobic organisms exchange air containing O₂ with air containing less O₂ and more CO₂.The CO₂ comes from

In the complete oxidation of glucose, six CO₂ molecules are formed per glucose molecule.The number of CO₂ molecules released by glycolysis is ___, by pyruvate oxidation is _, and by the citric acid cycle is _____.

Refer to the equation below, summarizing a step in lactic acid fermentation. Pyruvate + NADH + H⁺  lactate + NAD⁺ In this reaction, which compound is oxidized and which is reduced?

In lactate fermentation, NAD⁺ is produced during the