MCQs Microbiology :: Energy Release and Conservation

1.
Organisms can synthesize ATP by oxidative phosphorylation when they

A. ferment
B. oxidize glucose to pyruvate
C. pass electrons from the oxidation of chlorophyll through an electron transport system
D. pass electrons to oxygen through an electron transport system containing cytochromes
Answer & Explanation
Answer: Option D
2.
How many molecules of carbon dioxide will be given off during ten turns of the Krebs cycle?

A. 10 B. 20
C. 30 D. 40
Answer & Explanation
Answer: Option B
3.
In cellular metabolism, O2 is used

A. to provide electrons for photophosphorylation
B. in glycolysis
C. as a terminal electron acceptor
D. in the Krebs cycle
Answer & Explanation
Answer: Option C
4.
In glycolysis, ATP is created by

A. photophosphorylation
B. the chemiosmotic mechanism
C. substrate level phosphorylation
D. the pentose phosphate pathway
Answer & Explanation
Answer: Option C
5.
Suppose a eukaryotic cell had a mutation that prevented the production of cytochrome c. As a result of this mutation, which of the following processes would not occur?

A. Cellular respiration
B. Photosynthesis
C. Mitosis
D. Cell wall synthesis
Answer & Explanation
Answer: Option A
6.
Which of the following best explains about the usefulness of the production of ethanol in yeast cells under anaerobic conditions?

A. Ethanol keeps the electron transport system functioning
B. Yeast would be unable to activate the enzymes of the Krebs cycle without ethanol
C. The process generates oxygen, which is required for glycolysis
D. The process regenerates NAD+, which is required for glycolysis
Answer & Explanation
Answer: Option D
7.
The final electron acceptor in the electron transport chain is

A. CoQ
B. a cytochrome
C. FMN
D. oxygen
Answer & Explanation
Answer: Option D
8.
The amount of energy (cal/mole) in an ATP molecule produced by a cell from glucose by fermentation is

A. greater than aerobic metabolism
B. less than aerobic metabolism
C. exactly or approximately equal to aerobic metabolism
D. none of the above
Answer & Explanation
Answer: Option C
9.
The enzymes for glycolysis are located

A. on the inner surface of the cell membrane
B. on the inner membrane of the mitochondrion
C. on the outer membrane of the chloroplast
D. in the cytoplasm
Answer & Explanation
Answer: Option D
10.
Glucose can be broken down to pyruvate by

A. Entner-Doudoroff pathway
B. tricarboxylic acid cycle
C. both (a) and (b)
D. none of these
Answer & Explanation
Answer: Option A
11.
In lactic acid fermentation, the final electron acceptor would be

A. fructose B. pyruvate
C. glucose D. acetyl-CoA
Answer & Explanation
Answer: Option B
12.
The amount of ATP that can be obtained by complete oxidation of a glucose by a bacterium is

A. greater than by a yeast cell
B. lesser than by a yeast cell
C. exactly or approximately equal to by a yeast cell
D. none of these
Answer & Explanation
Answer: Option A
13.
Which of the following is accomplished in chemiosmosis?

A. The oxidation of ATP
B. The oxidation of water
C. The oxidation of NADH
D. The oxidation of CO2
Answer & Explanation
Answer: Option C
14.
A yeast or fungal cell produces how many net ATP molecules per molecule of glucose when completely oxidized?

A. 32 B. 34
C. 36 D. 38
Answer & Explanation
Answer: Option C
15.
Before most molecules can enter the Krebs citric acid cycle, they must be converted to

A. citric acid
B. oxaloacetic acid
C. NADH or FADH
D. acetyl-CoA
Answer & Explanation
Answer: Option D
16.
How many oxygen molecules are required in the fermentation of one molecule of glucose to ethanol and CO2?

A. 0 B. 1
C. 2 D. 36
Answer & Explanation
Answer: Option A
17.
Most bacterial fermentations yield how many net ATP molecules per molecule of glucose?

A. 1 B. 2
C. 4 D. 6
Answer & Explanation
Answer: Option B
18.
The amount of ATP produced by a cell from glucose when metabolizing it by fermentation means is

A. greater than by aerobic metabolism
B. lesser than by aerobic metabolism
C. exactly or approximately equal to by aerobic metabolism
D. none of these
Answer & Explanation
Answer: Option B
19.
Which one of the following is produced in the greatest numbers during one turn of the Krebs cycle?

A. NADH B. Acetyl-CoA
C. FADH2 D. ATP
Answer & Explanation
Answer: Option A
20.
Aerobic respiration differs from anaerobic respiration in which of the following respects?

A. Anaerobic respiration is glycolysis
B. Aerobic respiration requires the electron transport chain
C. The final electron acceptors are different
D. Aerobic respiration produces less ATP
Answer & Explanation
Answer: Option C
21.
For each pair of electrons passing from NADH located inside the mitochondria to oxygen, how many ATP molecules can be generated?

A. 1 B. 2
C. 3 D. 4
Answer & Explanation
Answer: Option C
22.
In anaerobic respiration, the final electron acceptor can be

A. oxygen B. nitrate
C. pyruvate D. acetyl-CoA
Answer & Explanation
Answer: Option B
23.
Which one of the following is not produced in any of the steps of glycolysis?

A. NAD+ B. NADH
C. ADP D. ATP
Answer & Explanation
Answer: Option A
24.
The number of ATP molecules produced from one glucose molecule by a bacterium producing lactic acid is

A. greater than producing ethanol
B. lesser than producing ethanol
C. approximately equal to producing ethanol
D. none of these
Answer & Explanation
Answer: Option C
25.
Which of the following is the most complete definition of fermentation?

A. Oxidation of glucose with organic molecules serving as electron acceptors
B. Complete catabolism of glucose to CO2 and HO2
C. Production of energy by substrate-level phosphorylation
D. Production of ethyl alcohol from glucose
Answer & Explanation
Answer: Option A
26.
The enzymes that catalyze the reactions of the Krebs cycle are found in which subcellular organelle of eukaryotes?

A. Mitochondrion
B. Chloroplast
C. Ribosome
D. Endoplasmic reticulum
Answer & Explanation
Answer: Option A
27.
Fatty acids are oxidized to acetyl-CoA by which of the following pathways?

A. β-oxidation
B. Entner-Doudoroff
C. pentose phosphate pathway
D. Embden-Meyerhof pathway
Answer & Explanation
Answer: Option A