When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?

When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?

A) The electrons gain free energy.
B) ATP synthase pumps protons by active transport.
C) NAD+ is oxidized.
D) The pH of the matrix increases.
E) The cytochromes phosphorylate ADP to form ATP.


Answer: D

For each mole of glucose (C6H12O6) oxidized by cellular respiration, how many moles of CO2 are released in the citric acid cycle (see Figure 7.1)?

For each mole of glucose (C6H12O6) oxidized by cellular respiration, how many moles of CO2 are released in the citric acid cycle (see Figure 7.1)?

A) 4
B) 12
C) 6
D) 3
E) 2


Answer: A

Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?

Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent? 

A) oxidative phosphorylation
B) glycolysis
C) electron transport
D) the citric acid cycle
E) chemiosmosis


Answer: B

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?

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 will decrease, and heat generation will increase.
B) ATP synthesis and heat generation will stay the same.
C) ATP synthesis and heat generation will both increase.
D) ATP synthesis will increase, and heat generation will decrease.
E) ATP synthesis and heat generation will both decrease.


Answer: A

The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation in eukaryotic cells is

The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation in eukaryotic cells is

A) oxidation of glucose to CO2 and water.
B) the thermodynamically favorable flow of electrons from NADH to the mitochondrial electron transport carriers.
C) the proton-motive force across the inner mitochondrial membrane.
D) the thermodynamically favorable transfer of phosphate from glycolysis and the citric acid cycle intermediate molecules of ADP.
E) the final transfer of electrons to oxygen.


Answer: C

Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle?

Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle? 

A) ?-ketoglutarate
B) malate or fumarate
C) pyruvate
D) succinyl CoA
E) acetyl CoA


Answer: E

During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?

During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?

A) ADP+?i
B) NADH
C) NAD+
D) ATP
E) FADH2


Answer: E

Even though plants carry on photosynthesis, plant cells still use their mitochondria for oxidation of pyruvate. When and where will this occur?

Even though plants carry on photosynthesis, plant cells still use their mitochondria for oxidation of pyruvate. When and where will this occur?

A) in photosynthesizing cells in the light and in other tissues in the dark
B) in nonphotosynthesizing cells only
C) in photosynthetic cells in the light, while photosynthesis occurs concurrently
D) in cells that are storing glucose only
E) in all cells all the time



Answer: E

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is

A) ADP.
B) water.
C) oxygen.
D) pyruvate.
E) NAD+


Answer: C

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is

A) the reduction of NAD+.
B) the restoration of the Na+/K+ balance across the membrane.
C) the formation of ATP.
D) the creation of a proton-motive force.
E) the lowering of pH in the mitochondrial matrix.


Answer: D

What carbon sources can yeast cells metabolize to make ATP from ADP under anaerobic conditions?

What carbon sources can yeast cells metabolize to make ATP from ADP under anaerobic conditions?

A) lactic acid
B) glucose
C) ethanol
D) pyruvate
E) either ethanol or lactic acid


Answer: B

Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water?

Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water?

A) fermentation
B) oxidation of pyruvate to acetyl CoA
C) glycolysis
D) oxidative phosphorylation (chemiosmosis)
E) citric acid cycle


Answer: D

Starting with one molecule of glucose, the energy-containing products of glycolysis are

Starting with one molecule of glucose, the energy-containing products of glycolysis are 

A) 6 CO2, 2 pyruvate, and 30 ATP.
B) 2 NAD+, 2 pyruvate, and 2 ATP.
C) 2 NADH, 2 pyruvate, and 2 ATP.
D) 2 FADH2, 2 pyruvate, and 4 ATP.
E) 6 CO2, 2 pyruvate, and 2 ATP.


Answer: C

Which of the following statements describes the results of this reaction? C6H12O6 + 6 O2 6 CO2 + 6 H2O+ Energy

Which of the following statements describes the results of this reaction? C6H12O6 + 6 O2 6 CO2 + 6 H2O+ Energy

A) O2 is oxidized and H2O is reduced.
B) O2 is reduced and CO2 is oxidized.
C) C6H12O6 is oxidized and O2 is reduced.
D) C6H12O6 is reduced and CO2 is oxidized.
E) CO2 is reduced and O2 is oxidized.


Answer: C

Which of the protein complexes labeled with Roman numerals in Figure 7.2 will transfer electrons to O2?

Which of the protein complexes labeled with Roman numerals in Figure 7.2 will transfer electrons to O2?

A) complex II
B) complex IV
C) complex III
D) complex I
E) All of the complexes can transfer electrons to O2.


Answer: B

What is the oxidizing agent in the following reaction? Pyruvate+ NADH + H+ Lactate+ NAD+

What is the oxidizing agent in the following reaction? Pyruvate+ NADH + H+ Lactate+ NAD+

A) lactate
B) pyruvate
C) NADH
D) NAD+
E) oxygen


Answer: B

Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?

Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?

A) 2%
B) 10%
C) 38%
D) 100%
E) 0%


Answer: D

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?

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 is converted to alcohol.
E) It reduces FADH2 to FAD+.


Answer: C

Most CO2 from catabolism is released during

Most CO2 from catabolism is released during 

A) oxidative phosphorylation.
B) glycolysis.
C) lactate fermentation.
D) electron transport.
E) the citric acid cycle.


Answer: E

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?

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) 6
C) 3
D) 30
E) 12


Answer: B