Question 1

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

Accepted Answer

Catabolism breaks down molecules to release energy, while anabolism uses energy to synthesize cellular material.

Question 2

A reaction has a standard free energy change ($\Delta G_0'$) of $-45$ kJ/mol. Which statement is correct about this reaction?

Accepted Answer

The reaction is exergonic and releases free energy.

Question 3

Which of the following equations correctly relates the change in free energy to the change in reduction potential for a redox reaction?

Accepted Answer

$\Delta G_0' = -nF\Delta E_0'$

Question 4

During aerobic respiration of glucose, which molecule acts as the terminal electron acceptor?

Accepted Answer

O$_2$

Question 5

Which of the following best explains why ATP is considered an energy-rich molecule?

Accepted Answer

It contains high-energy phosphate bonds that release significant free energy upon hydrolysis.

Question 6

A microorganism that uses light as an energy source and CO$_2$ as a carbon source is best classified as a:

Accepted Answer

Photoautotroph

Question 7

Which of the following statements about NAD$^+$/NADH is correct?

Accepted Answer

NAD$^+$ is reduced to NADH by accepting two electrons and one proton.

Question 8

Which process directly generates ATP by transferring a phosphate group from a high-energy substrate to ADP?

Accepted Answer

Substrate-level phosphorylation

Question 9

In the glycolytic pathway, what is the net yield of ATP and NADH per molecule of glucose?

Accepted Answer

2 ATP, 2 NADH

Question 10

Which of the following is a key difference between fermentation and respiration in microorganisms?

Accepted Answer

Fermentation generates ATP only by substrate-level phosphorylation, while respiration can generate ATP by oxidative phosphorylation.

Question 11

Which enzyme catalyzes the first step of the Calvin cycle, fixing CO$_2$ into organic molecules?

Accepted Answer

RubisCO (ribulose bisphosphate carboxylase/oxygenase)

Question 12

A bacterium is growing in an environment lacking O$_2$ but containing nitrate (NO$_3^-$). Which process is most likely being used for energy conservation?

Accepted Answer

Anaerobic respiration

Question 13

Which of the following best describes the function of ATP synthase in the cell?

Accepted Answer

It uses the proton motive force to synthesize ATP from ADP and Pi.

Question 14

Which statement about the glyoxylate cycle is correct?

Accepted Answer

It is used to catabolize C$_2$ compounds like acetate and bypasses the decarboxylation steps of the citric acid cycle.

Question 15

Which of the following is a major reason why nitrogenase is inhibited by oxygen?

Accepted Answer

Oxygen irreversibly oxidizes the iron-molybdenum cofactor in nitrogenase.

Question 16

Which of the following best explains why chemolithotrophs often use reverse electron transport?

Accepted Answer

To reduce NAD$^+$ to NADH for biosynthetic reactions when their electron donors have higher (less negative) reduction potentials than NAD$^+$.

Question 17

Which of the following is a correct statement about the pentose phosphate pathway?

Accepted Answer

It generates NADPH and ribulose-5-phosphate for biosynthesis.

Question 18

Which of the following is a function of glutamine synthetase in bacterial cells?

Accepted Answer

It incorporates ammonia into glutamate to form glutamine, using ATP.

Question 19

Which statement best describes the role of coenzymes in enzyme catalysis?

Accepted Answer

They are loosely bound, often derived from vitamins, and shuttle small molecules or electrons during catalysis.

Microbial Metabolism: Fundamentals, Pathways, and Biosynthesis

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