Bio 111 Exam 3 CH 9

Which of the listed statements describes the results of the following 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) O2 is reduced and CO2 is oxidized.

A) C6H12O6 is oxidized and O2 is reduced.

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

B) oxidized

Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis? A) 0% B) 2% C) 38% D) 100%

D) 100%

7) Which of the following statements about NAD+ is true? 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+ can donate electrons for use in oxidative phosphorylation. D) In the absence of NAD+, glycolysis can still function.

A) NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.

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

A) reduced, and energy is released

Starting with one molecule of glucose, the energy-containing products of glycolysis are _____. A) 2 NAD+, 2 pyruvate, and 2 ATP B) 2 NADH, 2 pyruvate, and 2 ATP C) 2 FADH2, 2 pyruvate, and 4 ATP D) 6 CO2, 2 pyruvate, and 2 ATP

B) 2 NADH, 2 pyruvate, and 2 ATP

A cell has enough available ATP to meet its needs for about 30 seconds. What is likely to happen when an athlete exhausts his or her ATP supply? A) He or she has to sit down and rest. B) Catabolic processes are activated that generate more ATP. C) ATP is transported into the cell from the circulatory system. D) Other cells take over, and the muscle cells that have used up their ATP cease to function.

B) Catabolic processes are activated that generate more ATP.

The oxygen consumed during cellular respiration is involved directly in which process or event? A) glycolysis B) accepting electrons at the end of the electron transport chain C) the citric acid cycle D) the oxidation of pyruvate to acetyl CoA

B) accepting electrons at the end of the electron transport chain

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

B) loses electrons and loses potential energy

14) 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.

B) two molecules of ATP are used and four molecules of ATP are produced.

The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mol and the free energy for the reduction of NAD+ to NADH is +53 kcal/mol. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed? A) Most of the free energy available from the oxidation of glucose is used in the production of ATP in glycolysis. B) Glycolysis is a very inefficient reaction, with much of the energy of glucose released as heat. C) Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis. D) There is no CO2 or water produced as products of glycolysis.

C) Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis.

Which kind of metabolic poison would most directly interfere with glycolysis? A) an agent that reacts with oxygen and depletes its concentration in the cell B) an agent that binds to pyruvate and inactivates it C) an agent that closely mimics the structure of glucose but is not metabolized D) an agent that reacts with NADH and oxidizes it to NAD+

C) an agent that closely mimics the structure of glucose but is not metabolized

Carbohydrates and fats are considered high-energy foods because they _____. A) have a lot of oxygen atoms. B) have no nitrogen in their makeup. C) have a lot of electrons associated with hydrogen. D) are easily reduced.

C) have a lot of electrons associated with hydrogen.

Substrate-level phosphorylation occurs _____. A) in glycolysis B) in the citric acid cycle C) in both glycolysis and the citric acid cycle D) during oxidative phosphorylation

C) in both glycolysis and the citric acid cycle

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

C) reduced

Most of the CO2 from the catabolism of glucose is released during _____. A) glycolysis B) electron transport C) chemiosmosis D) the citric acid cycle

D) the citric acid cycle