Question 1

Which of the following best describes the function of the cytoplasmic membrane in prokaryotic cells?

Accepted Answer

It surrounds the cytoplasm and acts as a selective permeability barrier.

Question 2

A bacterium is found to have a thick peptidoglycan layer and no outer membrane. Which type of cell envelope does it most likely possess?

Accepted Answer

Gram-positive

Question 3

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

Accepted Answer

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

Question 4

Which of the following statements about endospores is CORRECT?

Accepted Answer

Endospores are highly differentiated dormant cells that can survive extreme conditions.

Question 5

A researcher is using a phase-contrast microscope to observe live bacterial cells. What is the main advantage of this technique?

Accepted Answer

It allows visualization of cells without staining, preserving their viability.

Question 6

Which of the following best explains why small prokaryotic cells can grow faster than larger ones?

Accepted Answer

They have a higher surface area-to-volume ratio, allowing more efficient nutrient uptake.

Question 7

Which of the following is a function of the bacterial capsule?

Accepted Answer

It protects the cell from phagocytosis and desiccation.

Question 8

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

Accepted Answer

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

Question 9

A bacterium is isolated from a hot spring with an optimal growth temperature of 75°C. Which term best describes this organism?

Accepted Answer

Thermophile

Question 10

Which of the following statements about the electron transport chain in aerobic respiration is TRUE?

Accepted Answer

Electrons are transferred from NADH to oxygen, generating a proton gradient across the membrane.

Question 11

Which of the following is a distinguishing feature of Gram-negative bacteria?

Accepted Answer

An outer membrane containing lipopolysaccharide (LPS)

Question 12

Which of the following best describes the process of chemotaxis in bacteria?

Accepted Answer

Directed movement in response to a chemical gradient

Question 13

Which of the following equations correctly represents the specific growth rate ($\mu$) of a microbial population?

Accepted Answer

$\mu = \frac{1}{N} \frac{dN}{dt}$

Question 14

Which of the following is a primary function of the bacterial flagellum?

Accepted Answer

Motility through rotation powered by the proton motive force

Question 15

Which of the following best explains why obligate anaerobes are killed by oxygen?

Accepted Answer

They lack enzymes such as catalase and superoxide dismutase to detoxify reactive oxygen species.

Question 16

Which of the following is a correct description of fermentation?

Accepted Answer

It generates ATP primarily by substrate-level phosphorylation.

Question 17

Which of the following is a function of the periplasmic space in Gram-negative bacteria?

Accepted Answer

It contains enzymes involved in nutrient acquisition and cell wall synthesis.

Question 18

Which of the following best describes the role of NAD+/NADH in microbial metabolism?

Accepted Answer

NADH acts as an electron carrier, donating electrons to the electron transport chain.

Question 19

Which of the following statements about antibiotics is TRUE?

Accepted Answer

They can inhibit cell wall synthesis, protein synthesis, or DNA replication in bacteria.

Question 20

Which of the following best explains why a bacterium with a mutation in the gene encoding ATP synthase would be unable to grow aerobically?

Accepted Answer

It would be unable to generate ATP using the proton motive force.

Comprehensive Study Notes: Microbial Cell Biology, Metabolism, and Growth (Based on Brock Biology of Microorganisms)

Study Guide - Practice Questions