Question 1

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

Accepted Answer

Catabolism involves the breakdown of complex molecules to release energy, while anabolism uses energy to build complex molecules from simpler ones.

Question 2

During glycolysis, what is the net gain of ATP molecules per molecule of glucose, and by which mechanism is this ATP generated?

Accepted Answer

2 ATP, generated by substrate-level phosphorylation

Question 3

Which of the following equations correctly represents the energy-releasing hydrolysis of ATP?

Accepted Answer

$ATP + H_2O \rightarrow ADP + P_i + H^+$

Question 4

In the chemiosmotic model for ATP generation, what is the immediate source of energy that drives ATP synthesis?

Accepted Answer

The proton motive force created by a proton gradient across a membrane

Question 5

Which of the following statements about oxidative phosphorylation is correct?

Accepted Answer

It requires an electron transport chain and uses oxygen as the final electron acceptor in aerobic respiration.

Question 6

A bacterium is growing in a medium with no oxygen but with nitrate ($NO_3^-$) available. Which process is it most likely using for energy production?

Accepted Answer

Anaerobic respiration, using $NO_3^-$ as the terminal electron acceptor

Question 7

Which of the following best explains why fermentation yields less ATP than aerobic respiration?

Accepted Answer

Fermentation does not use an electron transport chain or oxidative phosphorylation.

Question 8

Which of the following is a product of the Krebs cycle per turn (per acetyl-CoA)?

Accepted Answer

3 NADH, 1 FADH$_2$, 1 ATP (or GTP), and 2 $CO_2$

Question 9

Which of the following best describes the role of NAD$^+$ in cellular metabolism?

Accepted Answer

It acts as an electron carrier, accepting electrons during redox reactions to become NADH.

Question 10

Which pathway is unique to some Gram-negative bacteria and is an alternative to glycolysis for glucose catabolism?

Accepted Answer

Entner-Doudoroff pathway

Question 11

A microbe that uses light as its energy source and $CO_2$ as its carbon source is best classified as which of the following?

Accepted Answer

Photoautotroph

Question 12

Which of the following statements about substrate-level phosphorylation is correct?

Accepted Answer

It involves the direct transfer of a phosphate group from a phosphorylated substrate to ADP.

Question 13

In oxygenic photosynthesis, what is the source of electrons for the light-dependent reactions?

Accepted Answer

Water ($H_2O$)

Question 14

Which of the following best summarizes the overall reaction for aerobic respiration of glucose?

Accepted Answer

$C_6H_{12}O_6 + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{energy}$

Question 15

Which of the following is NOT a product of fermentation?

Accepted Answer

Water ($H_2O$)

Question 16

Which of the following best describes the function of the pentose phosphate pathway?

Accepted Answer

It generates NADPH and pentoses for biosynthesis.

Question 17

A cell is exposed to a chemical that inhibits ATP synthase. Which process will be most directly affected?

Accepted Answer

Chemiosmotic generation of ATP

Question 18

Which of the following is true regarding the Calvin-Benson cycle?

Accepted Answer

It is a light-independent pathway that fixes $CO_2$ into organic molecules.

Question 19

Which of the following best explains why oxygen is required for aerobic respiration?

Accepted Answer

Oxygen acts as the terminal electron acceptor in the electron transport chain.

Question 20

A chemoheterotroph obtains its energy and carbon from which sources?

Accepted Answer

Energy from chemical compounds and carbon from organic compounds

Microbial Metabolism: Foundations and Pathways

Study Guide - Practice Questions