Question 1

Which of the following best describes the difference between catabolic and anabolic reactions in microbial metabolism?

Accepted Answer

Catabolic reactions break down complex molecules and release energy, while anabolic reactions use energy to build complex molecules.

Question 2

During glycolysis, what is the net gain of ATP molecules per molecule of glucose oxidized?

Accepted Answer

$2$

Question 3

Which of the following statements about oxidation-reduction (redox) reactions is correct?

Accepted Answer

Oxidation is the removal of electrons, and reduction is the gain of electrons.

Question 4

In aerobic respiration, what is the final electron acceptor in the electron transport chain?

Accepted Answer

Molecular oxygen ($O_2$)

Question 5

Which of the following equations correctly represents the overall reaction for aerobic respiration?

Accepted Answer

$C_6H_{12}O_6 + 6O_2 + 38ADP + 38P_i \rightarrow 6CO_2 + 6H_2O + 38ATP$

Question 6

Where does the Krebs cycle occur in prokaryotic cells?

Accepted Answer

Foldings of the cell membrane

Question 7

Which process does NOT occur during fermentation?

Accepted Answer

Electron transport chain

Question 8

A patient’s muscle cells are deprived of oxygen during intense exercise. Which metabolic pathway will primarily provide ATP under these conditions?

Accepted Answer

Lactic acid fermentation

Question 9

Which of the following best explains why anaerobic respiration yields less energy than aerobic respiration?

Accepted Answer

The final electron acceptor in anaerobic respiration is not oxygen, resulting in less efficient ATP production.

Question 10

Which of the following is a correct description of chemiosmosis in the context of ATP synthesis?

Accepted Answer

Protons are pumped across the membrane, creating a gradient that drives ATP synthesis as they flow back through ATP synthase.

Question 11

Which of the following is true about lactic acid fermentation?

Accepted Answer

It produces lactic acid and regenerates NAD$^+$ from NADH.

Question 12

What is the role of NAD$^+$ in cellular respiration?

Accepted Answer

It acts as an electron carrier, accepting electrons during glycolysis and the Krebs cycle.

Question 13

Which of the following is a product of the Krebs cycle?

Accepted Answer

NADH

Question 14

A bacterium is growing in an environment without oxygen but still produces ATP using an electron transport chain. What is the most likely explanation?

Accepted Answer

The bacterium is using anaerobic respiration with a non-oxygen final electron acceptor.

Question 15

Which of the following best describes the fate of pyruvic acid in fermentation?

Accepted Answer

It is reduced by NADH to form fermentation end-products.

Question 16

Which of the following is a distinguishing feature of heterolactic fermentation compared to homolactic fermentation?

Accepted Answer

Heterolactic fermentation produces lactic acid and other compounds.

Question 17

Which of the following steps is NOT shared by both aerobic and anaerobic respiration?

Accepted Answer

Use of oxygen as the final electron acceptor

Question 18

A mutation prevents a bacterium from producing ATP synthase. Which process would be most directly affected?

Accepted Answer

Chemiosmotic generation of ATP during electron transport

Question 19

Which of the following best explains why fermentation is important for cells under anaerobic conditions?

Accepted Answer

It regenerates NAD$^+$, allowing glycolysis to continue producing ATP.

Question 20

Which of the following is a real-world application of microbial fermentation?

Accepted Answer

Production of yogurt from milk by Lactobacillus spp.

Microbial Metabolism: Study Guide for College Microbiology

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