Chapter 9

In addition to ATP, what are the end products of glycolysis? A) CO2 and H2O B) CO2 and pyruvate C) NADH and pyruvate D) CO2 and NADH E) H2O, FADH2, and citrate

C

When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the molecule becomes A) dehydrogenated. B) oxidized. C) reduced. D) redoxed. E) hydrolyzed.

C

How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate? A) two B) four C) six D) eight E) ten

A

The ATP made during glycolysis is generated by A) substrate-level phosphorylation. B) electron transport. C) photophosphorylation. D) chemiosmosis. E) oxidation of NADH to NAD+.

A

When electrons move closer to a more electronegative atom, what happens? A) The more electronegative atom is reduced, and energy is released. B) The more electronegative atom is reduced, and energy is consumed. C) The more electronegative atom is oxidized, and energy is consumed. D) The more electronegative atom is oxidized, and energy is released. E) The more electronegative atom is reduced, and entropy decreases.

A

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)

A

Which of the following statements describes NAD+? A) NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. B) NAD+ has more chemical energy than NADH. C) NAD+ is oxidized by the action of hydrogenases. D) NAD+ can donate electrons for use in oxidative phosphorylation. E) In the absence of NAD+, glycolysis can still function.

A

Which of the following statements describes the results of this reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy A) C6H12O6 is oxidized and O2 is reduced. B) O2 is oxidized and H2O is reduced. C) CO2 is reduced and O2 is oxidized. D) C6H12O6 is reduced and CO2 is oxidized. E) O2 is reduced and CO2 is oxidized.

A

An electron loses potential energy when it A) shifts to a less electronegative atom. B) shifts to a more electronegative atom. C) increases its kinetic energy. D) increases its activity as an oxidizing agent. E) moves further away from the nucleus of the atom.

B

In glycolysis, for each molecule of glucose oxidized to pyruvate A) two molecules of ATP are used and two molecules of ATP are produced. B) two molecules of ATP are used and four molecules of ATP are produced. C) four molecules of ATP are used and two molecules of ATP are produced. D) two molecules of ATP are used and six molecules of ATP are produced. E) six molecules of ATP are used and six molecules of ATP are produced.

B

The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction A) gains electrons and gains potential energy. B) loses electrons and loses potential energy. C) gains electrons and loses potential energy. D) loses electrons and gains potential energy. E) neither gains nor loses electrons, but gains or loses potential energy.

B

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.

B

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+

B

What is the term for metabolic pathways that release stored energy by breaking down complex molecules? A) anabolic pathways B) catabolic pathways C) fermentation pathways D) thermodynamic pathways E) bioenergetic pathways

B

Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent? A) electron transport B) glycolysis C) the citric acid cycle D) oxidative phosphorylation E) chemiosmosis

B

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes A) hydrolyzed. B) hydrogenated. C) oxidized. D) reduced. E) an oxidizing agent.

C

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.

D

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the A) formation of ATP. B) reduction of NAD+. C) restoration of the Na+/K+ balance across the membrane. D) creation of a proton-motive force. E) lowering of pH in the mitochondrial matrix.

D

Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO2) from one molecule of pyruvate? A) lactate B) glyceraldehydes-3-phosphate C) oxaloacetate D) acetyl CoA E) citrate

D

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)

E