Question 1

Which of the following best describes the function of ATP synthase in bacterial cells?

Accepted Answer

It synthesizes ATP from ADP and inorganic phosphate using the proton motive force.

Question 2

During aerobic respiration, which of the following statements about the electron transport chain (ETC) is correct?

Accepted Answer

The ETC pumps protons across the membrane, creating a proton gradient used by ATP synthase.

Question 3

Which of the following equations correctly represents the standard free energy change ($\Delta G^\circ'$) for a redox reaction?

Accepted Answer

$\Delta G^\circ' = -nF\Delta E^\circ'$

Question 4

A bacterium is placed in an environment with no oxygen but an abundant supply of nitrate. Which metabolic process is most likely to occur?

Accepted Answer

Anaerobic respiration using nitrate as the terminal electron acceptor

Question 5

Which of the following best distinguishes between homolactic and heterolactic fermentation?

Accepted Answer

Homolactic fermentation produces only lactic acid, while heterolactic fermentation produces lactic acid, ethanol, and CO$_2$.

Question 6

Which of the following is a direct method for measuring bacterial growth?

Accepted Answer

Counting colonies on a plate (plate count method)

Question 7

A patient is diagnosed with a bacterial infection. The pathogen is a Gram-negative rod that is transmitted via contaminated water and causes severe diarrhea. Which of the following is the most likely route of transmission?

Accepted Answer

Fecal-oral route

Question 8

Which of the following best explains why endospores are resistant to harsh environmental conditions?

Accepted Answer

They have a thick protein coat and dehydrated core that protect DNA and enzymes.

Question 9

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

Accepted Answer

NADH donates electrons to the electron transport chain, becoming oxidized to NAD$^+$.

Question 10

During the exponential (log) phase of bacterial growth, which of the following occurs?

Accepted Answer

Cells are dividing at a constant and maximum rate.

Question 11

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

ATP is generated directly by transferring a phosphate group from a substrate to ADP.

Question 12

A bacterial culture is grown in a medium containing only glucose as a carbon source. After 24 hours, the culture medium contains lactic acid but no ethanol or CO$_2$. Which metabolic pathway is most likely active?

Accepted Answer

Homolactic fermentation

Question 13

Which of the following is a key function of bacterial flagella?

Accepted Answer

Facilitating chemotaxis by rotating to move the cell toward or away from stimuli

Question 14

Which of the following best describes the role of the proton motive force (PMF) in bacterial cells?

Accepted Answer

It is used to drive the synthesis of ATP via ATP synthase.

Question 15

Which of the following is NOT a major nutritional type of microorganisms based on energy and carbon sources?

Accepted Answer

Photofermentotroph

Question 16

Which of the following best explains the difference between catabolism and anabolism?

Accepted Answer

Catabolism breaks down molecules to release energy, while anabolism builds molecules using energy.

Question 17

A bacterial cell is observed to move toward a source of glucose. This behavior is best described as:

Accepted Answer

Positive chemotaxis

Question 18

Which of the following is a disadvantage of using turbidity measurements to estimate bacterial growth?

Accepted Answer

It cannot distinguish between live and dead cells.

Question 19

Which of the following best describes the function of bacterial endospores?

Accepted Answer

They allow bacteria to survive extreme environmental conditions.

Question 20

Which of the following best describes the process of binary fission in bacteria?

Accepted Answer

A single cell divides into two genetically identical daughter cells.

Microbial Structure, Metabolism, and Growth: Study Guide

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