Quiz 3.1

In the absence of oxygen, yeast cells can obtain energy by fermentation, which results in the production of which of the following sets of molecules? A. ATP, CO2, and ethanol (ethyl alcohol) B. ATP, CO2, and lactate C. ATP, NADH, and ethanol D. ATP, CO2, and acetyl CoA

A. ATP, CO2, and ethanol (ethyl alcohol)

What happens to a glucose molecule when it loses a hydrogen atom as the result of an oxidation-reduction reaction? A. The glucose molecule is oxidized. B. The glucose molecule is an oxidizing agent. C. The glucose molecule is hydrolyzed. D. The glucose molecule is reduced.

A. The glucose molecule is oxidized.

Why are carbohydrates and fats frequently considered high-energy foods? A. They contain many electrons associated with hydrogen atoms. B. They contain no nitrogen atoms. C. They contain many oxygen atoms. D. They are strong oxidizing molecules.

A. They contain many electrons associated with hydrogen atoms.

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

A. reduced

An organism is discovered that thrives in both the presence and absence of oxygen. Interestingly, as oxygen is removed from the organism's environment, the rate of sugar consumption increases while the growth rate decreases. What do these observations suggest about the likely identity of this organism? A. It is an unremarkable eukaryotic organism. B. It is a facultative anaerobic organism. C. It is a photosynthetic organism. D. It is an obligate anaerobic organism.

B. It is a facultative anaerobic organism.

Which of the following metabolic processes take place in the cytosol of a eukaryotic cell? A. fermentation and chemiosmosis B. glycolysis and fermentation C. citric acid cycle D. oxidation of pyruvate to acetyl CoA

B. glycolysis and fermentation

Water is one of the end products of aerobic respiration. What is the source of the oxygen atom used in formation of the water? A. pyruvate (C3H3O3-) B. molecular oxygen (O2) C. glucose (C6H12O6) D. carbon dioxide (CO2)

B. molecular oxygen (O2)

Which of the following statements best describes the primary role played by oxygen in cellular respiration? A. It serves as an acceptor for carbon, forming CO2 in the citric acid cycle. B. It yields energy in the form of ATP as it is passed down the electron transport chain. C. It serves as the final acceptor for electrons from the electron transport chain. D. It oxidizes glucose to form two molecules of pyruvate.

C. It serves as the final acceptor for electrons from the electron transport chain.

13 Yeast cells that have defective mitochondria incapable of respiration will be able to grow by catabolizing which of the following carbon sources for energy? A. amino acids B. fatty acids C. glucose D. cholesterol

C. glucose

Which of the following statements describes a primary function of both alcohol fermentation and lactic acid fermentation? A. reduction of FAD to FADH2 B. hydrolysis of ATP to ADP + i C. oxidation of NADH to NAD+ D. reduction of NAD+ to NADH

C. oxidation of NADH to NAD+

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration? A. fermentation and glycolysis B. glycolysis and the oxidation of pyruvate to acetyl CoA C. oxidation of pyruvate to acetyl CoA and the citric acid cycle D. oxidative phosphorylation and fermentation

C. oxidation of pyruvate to acetyl CoA and the citric acid cycle

Why is glycolysis considered to be one of the first metabolic pathways to have evolved? A. It is present in prokaryotic cells but not in eukaryotic cells. B. It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells. C. It produces much less ATP than does oxidative phosphorylation. D. It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.

D. It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.

Which of the following statements describes what happens to a molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction? A. It gains electrons and gains potential energy. B. It loses electrons and gains potential energy. C. It gains electrons and loses potential energy. D. It loses electrons and loses potential energy.

D. It loses electrons and loses potential energy

Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? A. the electron transport chain B. reduction of pyruvate to lactate C. the citric acid cycle D. glycolysis

D. glycolysis

Even though plants cells carry out photosynthesis, they still use their mitochondria for oxidation of pyruvate. Under what conditions will plant cell mitochondria be active in this process? A. only in cells that store glucose in the form of starch and only in the dark B. only in photosynthetic cells in the light, while photosynthesis occurs concurrently C. in photosynthesizing cells in the light, and in other cells in the dark D. in all cells, with or without light

D. in all cells, with or without light