Question 1

Which of the following statements best describes the difference between Gram-positive and Gram-negative bacterial cell walls?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer and lack an outer membrane, while Gram-negative bacteria have a thin peptidoglycan layer and possess an outer membrane.

Question 2

Which of the following best explains why penicillin is generally ineffective against Gram-negative bacteria?

Accepted Answer

The outer membrane of Gram-negative bacteria acts as a barrier, preventing penicillin from reaching the peptidoglycan layer.

Question 3

Which of the following is a unique feature of archaeal membranes compared to bacterial membranes?

Accepted Answer

Archaeal membranes contain ether-linked isoprenoid chains instead of fatty acids.

Question 4

A researcher treats a bacterial culture with lysozyme. Which of the following outcomes is most likely?

Accepted Answer

The peptidoglycan layer is degraded, leading to cell lysis.

Question 5

Which of the following best describes the function of the proton motive force (pmf) in bacterial cells?

Accepted Answer

It is the main energy source for ATP synthesis via ATP synthase.

Question 6

Which of the following transport systems directly uses ATP hydrolysis to move substances across the membrane?

Accepted Answer

ABC transporter

Question 7

Which of the following statements about Mycoplasma species is correct?

Accepted Answer

They lack a cell wall and incorporate sterols into their plasma membrane.

Question 8

Which of the following is a function of bacterial capsules?

Accepted Answer

Protecting cells from desiccation and aiding in evasion of host immune responses

Question 9

Which of the following best describes the structure of peptidoglycan?

Accepted Answer

A polymer of N-acetylglucosamine and N-acetylmuramic acid cross-linked by short peptides

Question 10

Which of the following is true regarding endospores?

Accepted Answer

They are highly resistant to heat, radiation, and chemicals due to their unique structure and low water content.

Question 11

Which of the following is a distinguishing feature of acid-fast bacterial cell walls?

Accepted Answer

A thick layer of mycolic acids and arabinogalactan over a thin peptidoglycan layer

Question 12

Which of the following best explains why L-forms of bacteria are resistant to penicillin?

Accepted Answer

They lack peptidoglycan, the target of penicillin.

Question 13

Which of the following structures is responsible for bacterial motility and is composed of a basal body, hook, and filament?

Accepted Answer

Flagellum

Question 14

Which of the following is a function of the S-layer in prokaryotes?

Accepted Answer

Providing structural support and protection against environmental stress

Question 15

Which of the following best describes the role of ATP synthase in the bacterial cytoplasmic membrane?

Accepted Answer

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

Question 16

Which of the following is a correct statement about the function of bacterial pili?

Accepted Answer

They allow for attachment to surfaces and facilitate DNA exchange during conjugation.

Question 17

Which of the following best describes the function of gas vesicles in cyanobacteria?

Accepted Answer

They provide buoyancy, allowing cells to position themselves optimally in the water column.

Question 18

Which of the following is a key difference between the cell envelopes of Chlamydiae and typical Gram-negative bacteria?

Accepted Answer

Chlamydiae possess a unique disulfide cross-linked outer membrane protein network instead of detectable peptidoglycan.

Question 19

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

Accepted Answer

Cells alternate between runs and tumbles, with the direction of runs biased toward attractants.

Microbial Cell Structure and Function: Study Notes for Chapter 2

Guida di studio - Domande di pratica

Study guide - Flashcard