Question 1

Which of the following best explains why commensal strains of Escherichia coli in the gut do not typically cause disease in healthy individuals?

Accepted Answer

They lack major virulence factors such as toxins, invasion proteins, and specialized secretion systems.

Question 2

Which structure is found in all prokaryotic cells and is essential for regulating the movement of molecules in and out of the cell?

Accepted Answer

Cell membrane

Question 3

A bacterium with a thick peptidoglycan layer and teichoic acids in its cell wall is most likely:

Accepted Answer

Gram-positive

Question 4

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

Accepted Answer

Immune evasion and resistance to phagocytosis

Question 5

Which of the following best describes the chemical structure of peptidoglycan?

Accepted Answer

Repeating units of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) crosslinked by peptide chains

Question 6

Which of the following is a unique feature of the cell membrane in Archaea compared to Bacteria?

Accepted Answer

L-glycerol ether bonds to fatty acids

Question 7

Penicillin inhibits bacterial growth by interfering with which cellular process?

Accepted Answer

Peptidoglycan crosslinking during cell wall synthesis

Question 8

Which of the following structures is primarily responsible for bacterial motility and can act as a virulence factor?

Accepted Answer

Flagellum

Question 9

A bacterium that moves toward a chemical attractant is exhibiting which type of taxis?

Accepted Answer

Chemotaxis

Question 10

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

Accepted Answer

Adherence to surfaces and host cells

Question 11

Which of the following is true about Gram-negative bacterial cell walls?

Accepted Answer

They have an outer membrane containing lipopolysaccharide (LPS).

Question 12

Which bacterial structure is most directly involved in the transfer of genetic material during conjugation?

Accepted Answer

Pilus

Question 13

Which of the following is a function of the bacterial cell wall?

Accepted Answer

Protection against osmotic lysis

Question 14

Which of the following best explains why Mycobacterium species are resistant to Gram stain dyes?

Accepted Answer

Their cell wall contains a high concentration of mycolic acid.

Question 15

Which of the following is NOT a function of the bacterial cell membrane?

Accepted Answer

Structural support against osmotic lysis

Question 16

Which of the following is a distinguishing feature of the bacterial capsule compared to the slime layer?

Accepted Answer

Capsule is tightly associated and provides immune evasion.

Question 17

Which of the following best describes the arrangement and shape of Staphylococcus bacteria?

Accepted Answer

Clusters of spherical cells

Question 18

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

Accepted Answer

Allow selective diffusion of hydrophilic molecules through the outer membrane

Question 19

Which of the following is a correct statement about the bacterial flagellum?

Accepted Answer

It is made of flagellin protein and is anchored by a basal body.

Question 20

Which of the following best describes the function of the bacterial slime layer?

Accepted Answer

Prevents desiccation and aids in biofilm formation

Prokaryotic Cell Structure: External and Internal Anatomy

Study Guide - Practice Questions