Question 1

Refer to the diagram below. The source of electrons for the electron transport chain is

Accepted Answer

A)  FADH2. 
B)  NADH-Q reductase complex. 
C)  NADH + H+. 
D)  ubiquinone. 
E)  Both a and c 
A)  FADH2. 
B)  NADH-Q reductase complex. 
C)  NADH + H+. 
D)  ubiquinone. 
E)  Both a and c

Question 2

In the conversion of succinate to fumarate, hydrogen atoms are transferred to FAD. The conversion of succinate and FAD to fumarate and FADH2 is an example of

Accepted Answer

A)  hydrolysis. 
B)  an allosteric reaction. 
C)  a metabolic pathway. 
D)  an aerobic reaction. 
E)  a redox reaction. 
A)  hydrolysis. 
B)  an allosteric reaction. 
C)  a metabolic pathway. 
D)  an aerobic reaction. 
E)  a redox reaction.

Question 3

Animals inhale air containing oxygen and exhale air with less oxygen and more carbon dioxide. After inhalation, the oxygen missing from the air will mostly be found in

Accepted Answer

A)  the carbon dioxide that is exhaled. 
B)  water. 
C)  organic molecules. 
D)  ethanol. 
E)  lactate. 
A)  the carbon dioxide that is exhaled. 
B)  water. 
C)  organic molecules. 
D)  ethanol. 
E)  lactate.

Question 4

Most ATP produced in our bodies is made

Accepted Answer

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

Question 5

Most of the ATP made during the complete oxidation of glucose to CO2 and water is

Accepted Answer

A)  made by the mitochondrial ATP synthase. 
B)  from substrate-level phosphorylation. 
C)  synthesized by the sodium-potassium ATPase. 
D)  synthesized in the cytosol. 
E)  made directly by the citric acid cycle. 
A)  made by the mitochondrial ATP synthase. 
B)  from substrate-level phosphorylation. 
C)  synthesized by the sodium-potassium ATPase. 
D)  synthesized in the cytosol. 
E)  made directly by the citric acid cycle.

Question 6

The chemiosmotic generation of ATP is driven by

Accepted Answer

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)  the proton-motive force. 
E)  isocitrate dehydrogenase. 
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)  the proton-motive force. 
E)  isocitrate dehydrogenase.

Question 7

The main control mechanism in glycolysis is the

Accepted Answer

A)  enzyme isocitrate dehydrogenase. 
B)  negative feedback of citrate accumulation. 
C)  presence or absence of oxygen. 
D)  enzyme phosphofructokinase. 
E)  supply of NAD. 
A)  enzyme isocitrate dehydrogenase. 
B)  negative feedback of citrate accumulation. 
C)  presence or absence of oxygen. 
D)  enzyme phosphofructokinase. 
E)  supply of NAD.

Question 8

The electron transport chain of mitochondria

Accepted Answer

A)  is present in the outer membrane of the mitochondrion. 
B)  contains cytochromes and proteins containing flavins (FA
D) . 
C)  reduces NAD+. 
D)  generates an H+ gradient such that the outside of the mitochondrion is more basic than the inside. 
E)  makes ATP. 
A)  is present in the outer membrane of the mitochondrion. 
B)  contains cytochromes and proteins containing flavins (FA
D) . 
C)  reduces NAD+. 
D)  generates an H+ gradient such that the outside of the mitochondrion is more basic than the inside. 
E)  makes ATP.

Question 9

When NADH donates two electrons to ubiquinone during respiration, ubiquinone is

Accepted Answer

A)  reduced. 
B)  oxidized. 
C)  phosphorylated. 
D)  aerobic. 
E)  hydrolyzed. 
A)  reduced. 
B)  oxidized. 
C)  phosphorylated. 
D)  aerobic. 
E)  hydrolyzed.

Question 10

Which of the following statements about metabolic pathways is true?

Accepted Answer

A)  Complex chemical transformations in the cell occur in a single reaction. 
B)  Each reaction requires oxygen. 
C)  In eukaryotes, they occur in the cytoplasm. 
D)  They vary from organism to organism. 
E)  Each one is regulated by specific enzymes. 
A)  Complex chemical transformations in the cell occur in a single reaction. 
B)  Each reaction requires oxygen. 
C)  In eukaryotes, they occur in the cytoplasm. 
D)  They vary from organism to organism. 
E)  Each one is regulated by specific enzymes.

Question 11

The end product of glycolysis is

Accepted Answer

A)  pyruvate. 
B)  the starting point for pyruvate oxidation. 
C)  the starting point for the fermentation pathway. 
D)  Both a and b 
E)  All of the above 
A)  pyruvate. 
B)  the starting point for pyruvate oxidation. 
C)  the starting point for the fermentation pathway. 
D)  Both a and b 
E)  All of the above

Question 12

Acetyl CoA

Accepted Answer

A)  is formed within mitochondria by the reduction of pyruvate. 
B)  is formed within mitochondria by the oxidation of fatty acids. 
C)  is formed in the cytoplasm by the oxidation of glucose. 
D)  is used for the synthesis of sugars. 
E)  is formed in the cytosol during the complete oxidation of glucose. 
A)  is formed within mitochondria by the reduction of pyruvate. 
B)  is formed within mitochondria by the oxidation of fatty acids. 
C)  is formed in the cytoplasm by the oxidation of glucose. 
D)  is used for the synthesis of sugars. 
E)  is formed in the cytosol during the complete oxidation of glucose.

Question 13

In alcoholic 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.

Question 14

Which of the statements below about the citric acid cycle is false?

Accepted Answer

A)  The cycle releases less energy than glycolysis. 
B)  CO2 is released during operation of the cycle. 
C)  The cycle takes place in the mitochondrial matrix. 
D)  The cycle requires NAD+ and FAD. 
E)  The cycle does not operate under anaerobic conditions. 
A)  The cycle releases less energy than glycolysis. 
B)  CO2 is released during operation of the cycle. 
C)  The cycle takes place in the mitochondrial matrix. 
D)  The cycle requires NAD+ and FAD. 
E)  The cycle does not operate under anaerobic conditions.

Question 15

When a cell needs energy, cellular respiration is regulated by isocitrate dehydrogenase, an enzyme of the citric acid cycle. This enzyme is stimulated by

Accepted Answer

A)  H+. 
B)  heat. 
C)  oxygen. 
D)  ADP. 
E)  None of the above 
A)  H+. 
B)  heat. 
C)  oxygen. 
D)  ADP. 
E)  None of the above

Question 16

Some of the free energy released by oxidation of pyruvate to acetate is stored in acetyl CoA. How does acetyl CoA store free energy?

Accepted Answer

A)  Acetyl CoA has a higher free energy than acetate. 
B)  Acetyl CoA is an electron carrier. 
C)  Acetyl CoA is a phosphate donor. 
D)  Acetate + CoA $\to$ acetyl CoA is an exergonic reaction. 
E)  Reduction of acetyl CoA is coupled to ATP synthesis. 
A)  Acetyl CoA has a higher free energy than acetate. 
B)  Acetyl CoA is an electron carrier. 
C)  Acetyl CoA is a phosphate donor. 
D)  Acetate + CoA $\to$ acetyl CoA is an exergonic reaction. 
E)  Reduction of acetyl CoA is coupled to ATP synthesis.

Question 17

The mitochondrial ATP synthase

Accepted Answer

A)  is an entirely integral membrane protein. 
B)  couples the synthesis of ATP to the flow of protons across the inner membrane from inside to out. 
C)  is a soluble protein located in the mitochondrial matrix. 
D)  makes ATP at the expense of the proton gradient established by electron transport. 
E)  usually hydrolyzes ATP to establish a proton gradient. 
A)  is an entirely integral membrane protein. 
B)  couples the synthesis of ATP to the flow of protons across the inner membrane from inside to out. 
C)  is a soluble protein located in the mitochondrial matrix. 
D)  makes ATP at the expense of the proton gradient established by electron transport. 
E)  usually hydrolyzes ATP to establish a proton gradient.

Question 18

Reagents, such as dinitrophenol, increase the permeability of the mitochondrial inner membrane to protons. The addition of dinitrophenol to a suspension of animal cells should

Accepted Answer

A)  decrease the rate of oxidation of NADH. 
B)  inhibit mitochondrial ATP synthesis. 
C)  increase lactic acid production. 
D)  decrease the rate of pyruvate oxidation. 
E)  stimulate ATP synthesis by mitochondria. 
A)  decrease the rate of oxidation of NADH. 
B)  inhibit mitochondrial ATP synthesis. 
C)  increase lactic acid production. 
D)  decrease the rate of pyruvate oxidation. 
E)  stimulate ATP synthesis by mitochondria.

Question 19

Oxygen is used by

Accepted Answer

A)  glycolysis. 
B)  the citric acid cycle. 
C)  the electron transport chain. 
D)  substrate-level phosphorylation. 
E)  ATP synthase. 
A)  glycolysis. 
B)  the citric acid cycle. 
C)  the electron transport chain. 
D)  substrate-level phosphorylation. 
E)  ATP synthase.

Question 20

When a molecule loses hydrogen atoms (as opposed to hydrogen ions), it becomes

Accepted Answer

A)  reduced. 
B)  oxidized. 
C)  redoxed. 
D)  hydrogenated. 
E)  hydrolyzed. 
A)  reduced. 
B)  oxidized. 
C)  redoxed. 
D)  hydrogenated. 
E)  hydrolyzed.

Exam 9: Pathways That Harvest Chemical Energy

Refer to the diagram below. The source of electrons for the electron transport chain is

In the conversion of succinate to fumarate, hydrogen atoms are transferred to FAD. The conversion of succinate and FAD to fumarate and FADH2 is an example of

Animals inhale air containing oxygen and exhale air with less oxygen and more carbon dioxide. After inhalation, the oxygen missing from the air will mostly be found in

Most ATP produced in our bodies is made

Most of the ATP made during the complete oxidation of glucose to CO2 and water is

The chemiosmotic generation of ATP is driven by

The main control mechanism in glycolysis is the

The electron transport chain of mitochondria

When NADH donates two electrons to ubiquinone during respiration, ubiquinone is

Which of the following statements about metabolic pathways is true?

The end product of glycolysis is

Acetyl CoA

In alcoholic fermentation, NAD+ is produced during the

Which of the statements below about the citric acid cycle is false?

When a cell needs energy, cellular respiration is regulated by isocitrate dehydrogenase, an enzyme of the citric acid cycle. This enzyme is stimulated by

Some of the free energy released by oxidation of pyruvate to acetate is stored in acetyl CoA. How does acetyl CoA store free energy?

The mitochondrial ATP synthase

Reagents, such as dinitrophenol, increase the permeability of the mitochondrial inner membrane to protons. The addition of dinitrophenol to a suspension of animal cells should

Oxygen is used by

When a molecule loses hydrogen atoms (as opposed to hydrogen ions), it becomes

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In the conversion of succinate to fumarate, hydrogen atoms are transferred to FAD. The conversion of succinate and FAD to fumarate and FADH₂ is an example of

Most of the ATP made during the complete oxidation of glucose to CO₂ and water is

In alcoholic fermentation, NAD⁺ is produced during the