Question 1

Which of the following best describes the difference between catabolism and anabolism in microbial metabolism?

Accepted Answer

Catabolism breaks down complex molecules to release energy, while anabolism uses energy to build complex molecules from simpler ones.

Question 2

Which of the following is NOT a component of an enzyme?

Accepted Answer

Substrate

Question 3

A researcher observes that an enzyme-catalyzed reaction slows down significantly when the temperature is increased from 37°C to 60°C. What is the most likely explanation?

Accepted Answer

The enzyme has become denatured at the higher temperature, losing its functional shape.

Question 4

Which of the following statements correctly distinguishes between competitive and noncompetitive enzyme inhibition?

Accepted Answer

Competitive inhibitors bind to the active site, preventing substrate binding, while noncompetitive inhibitors bind elsewhere, altering enzyme function.

Question 5

Given the following redox reaction: $\mathrm{NAD}^+ + 2e^- + 2H^+ \rightarrow \mathrm{NADH} + H^+$, which molecule is reduced?

Accepted Answer

$\mathrm{NAD}^+$

Question 6

Which of the following is NOT a type of phosphorylation that generates ATP in microbial cells?

Accepted Answer

Hydrolytic phosphorylation

Question 7

During glycolysis, what are the net products generated from one molecule of glucose?

Accepted Answer

2 ATP, 2 NADH, and 2 pyruvate

Question 8

Which of the following best describes the process of oxidative phosphorylation?

Accepted Answer

ATP is generated using energy released by electrons moving through the electron transport chain to power ATP synthase.

Question 9

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

Accepted Answer

$\mathrm{O}_2$

Question 10

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation regenerates NAD$^+$ from NADH, allowing glycolysis to continue in the absence of oxygen.

Question 11

A microbiologist is testing two unknown bacterial samples using biochemical tests. Sample A produces gas in a Durham tube during glucose fermentation, while Sample B does not. What can be inferred about the metabolism of Sample A?

Accepted Answer

Sample A is capable of fermentative metabolism that produces gas as a byproduct.

Question 12

Which of the following best describes an amphibolic pathway?

Accepted Answer

A pathway that can function in both catabolic and anabolic processes.

Question 13

Which of the following is a key difference between aerobic respiration and anaerobic respiration in bacteria?

Accepted Answer

Aerobic respiration uses $\mathrm{O}_2$ as the final electron acceptor, while anaerobic respiration uses inorganic molecules such as $\mathrm{NO}_3^-$ or $\mathrm{SO}_4^{2-}$.

Question 14

Which of the following best explains why increasing substrate concentration can overcome the effects of a competitive inhibitor but not a noncompetitive inhibitor?

Accepted Answer

Competitive inhibitors bind reversibly to the active site, so excess substrate can outcompete the inhibitor, while noncompetitive inhibitors bind elsewhere and change enzyme shape.

Question 15

A patient is diagnosed with a mitochondrial disorder that impairs the electron transport chain. Which process will be most directly affected?

Accepted Answer

Oxidative phosphorylation

Question 16

Which of the following is a correct sequence of events in the complete aerobic breakdown of glucose?

Accepted Answer

Glycolysis $\rightarrow$ Krebs cycle $\rightarrow$ Electron transport chain

Question 17

Which of the following best describes the role of ATP in cellular metabolism?

Accepted Answer

ATP is a universal energy currency that couples catabolic and anabolic reactions.

Question 18

Which of the following is a real-life example of substrate-level phosphorylation?

Accepted Answer

ATP generation during glycolysis when 1,3-bisphosphoglycerate donates a phosphate to ADP.

Question 19

Which of the following best explains why bacteria can be identified using biochemical tests based on metabolism?

Accepted Answer

Different bacteria possess unique sets of enzymes that catalyze specific metabolic reactions.

Question 20

Which of the following statements about photophosphorylation is correct?

Accepted Answer

Photophosphorylation uses light energy to drive the synthesis of ATP via an electron transport chain.

Microbial Metabolism: Key Concepts and Processes

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