Question 1

Which of the following best explains why small bacterial cells can grow and replicate faster than larger cells?

Accepted Answer

Small cells have a higher surface area to volume ratio, which supports a greater rate of nutrient exchange.

Question 2

A bacterium is observed to have a thick peptidoglycan layer and teichoic acids in its cell wall. Which type of cell wall does it possess?

Accepted Answer

Gram-positive

Question 3

Which component of the Gram-negative bacterial cell wall is responsible for its toxicity (endotoxin activity) in humans?

Accepted Answer

Lipid A of lipopolysaccharide (LPS)

Question 4

During Gram staining, why do Gram-positive cells retain the crystal violet-iodine complex after alcohol-acetone treatment?

Accepted Answer

Their thick peptidoglycan layer traps the dye complex.

Question 5

Which of the following equations correctly represents the surface area to volume ratio for a spherical bacterial cell of radius $$r$$?

Accepted Answer

$$\frac{4\pi r^2$}{\frac{4}{3}\pi r^3$}$$

Question 6

A patient is infected with a bacterium that lacks a cell wall. Which antibiotic would likely be ineffective against this organism?

Accepted Answer

Penicillin

Question 7

Which structure allows bacteria to adhere to surfaces and evade immune defenses, and is primarily composed of carbohydrates?

Accepted Answer

Glycocalyx (capsule or slime layer)

Question 8

Which of the following best describes the function of the bacterial plasma membrane?

Accepted Answer

Acts as a selective barrier and site of energy transformation

Question 9

A scientist observes a bacterium with peritrichous flagella. What does this mean?

Accepted Answer

Flagella are distributed all over the cell surface.

Question 10

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

Accepted Answer

Transfer of genetic material during conjugation

Question 11

Which of the following statements about bacterial endospores is TRUE?

Accepted Answer

They are highly resistant to heat, desiccation, and chemicals.

Question 12

Which of the following best describes the composition of peptidoglycan?

Accepted Answer

Repeating units of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) cross-linked by tetrapeptide chains

Question 13

Which of the following is a unique feature of Gram-negative bacteria compared to Gram-positive bacteria?

Accepted Answer

Presence of an outer membrane containing lipopolysaccharide (LPS)

Question 14

A mutation causes a bacterium to lose its O side chain in the LPS. Which of the following is a likely consequence?

Accepted Answer

Reduced ability to evade host immune detection

Question 15

Which of the following best explains why electron microscopy requires samples to be fixed and stained with heavy metals?

Accepted Answer

Electrons interact poorly with biological atoms and require contrast from heavy elements.

Question 16

Which of the following is a function of bacterial storage granules?

Accepted Answer

Store organic and inorganic molecules such as phosphate

Question 17

Which of the following is TRUE regarding the bacterial chromosome?

Accepted Answer

It is a single, circular, double-stranded DNA molecule located in the nucleoid.

Question 18

Which of the following best describes the function of fimbriae?

Accepted Answer

Mediating adherence to target surfaces

Question 19

Which of the following is a distinguishing feature of eukaryotic microbial cells compared to prokaryotic cells?

Accepted Answer

Presence of membrane-bound organelles such as mitochondria and nucleus

Question 20

Which of the following best describes the role of the cytoskeleton in eukaryotic cells?

Accepted Answer

Provides structural support and facilitates intracellular transport

Microbial Cell Structure and Function: A Comprehensive Study Guide

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