Question 1

Which of the following best describes the main function of the cytoplasmic (cell) membrane in bacteria?

Accepted Answer

It acts as a selective permeability barrier, allowing nutrients in and waste out.

Question 2

Which structural feature is unique to Gram-negative bacteria and not found in Gram-positive bacteria?

Accepted Answer

Outer membrane containing lipopolysaccharide (LPS)

Question 3

A bacterium is found to have a cell wall composed of alternating N-acetylglucosamine and N-acetylmuramic acid, with β-1,4 glycosidic bonds. Which enzyme can destroy this structure?

Accepted Answer

Lysozyme

Question 4

Which of the following is a function of bacterial capsules?

Accepted Answer

Preventing dehydration and aiding in evasion of phagocytosis

Question 5

Which of the following statements about archaeal membranes is correct?

Accepted Answer

They contain isoprene chains and ether linkages.

Question 6

A Gram-positive bacterium is exposed to penicillin. What is the most likely effect?

Accepted Answer

Disruption of peptide cross-links in peptidoglycan, leading to cell lysis

Question 7

Which of the following best explains why Mycoplasma pneumoniae is resistant to penicillin?

Accepted Answer

It lacks a cell wall.

Question 8

Which component of the Gram-negative outer membrane is responsible for its toxicity in humans?

Accepted Answer

Lipid A of lipopolysaccharide (LPS)

Question 9

Which of the following is a correct description of the function of bacterial endospores?

Accepted Answer

They allow bacteria to survive extreme environmental conditions.

Question 10

Which of the following is NOT a function of the S-layer in Archaea?

Accepted Answer

Serving as the main site of ATP synthesis

Question 11

A scientist discovers a microorganism with a cell wall containing N-acetyltalosaminuronic acid and β-1,3 glycosidic bonds. Which group does this organism most likely belong to?

Accepted Answer

Methanogenic Archaea

Question 12

Which of the following structures is primarily responsible for bacterial conjugation?

Accepted Answer

Sex pilus

Question 13

Which of the following best describes the arrangement of peptidoglycan in Gram-positive bacteria?

Accepted Answer

Multiple layers with extensive peptide cross-linking, often including peptide interbridges

Question 14

Which of the following is a distinguishing feature of the cytoplasmic membrane in Archaea compared to Bacteria?

Accepted Answer

Presence of phosphoglycerol diethers and tetraethers

Question 15

Which of the following is a correct statement about the function of gas vesicles in cyanobacteria?

Accepted Answer

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

Question 16

Which of the following is a correct description of the role of porins in Gram-negative bacteria?

Accepted Answer

They form channels in the outer membrane for the passage of small molecules.

Question 17

Which of the following best explains why penicillin is ineffective against methanogenic Archaea?

Accepted Answer

Their cell walls lack peptidoglycan and contain pseudomurein with β-1,3 glycosidic bonds.

Question 18

Which of the following is a correct statement about the function of inclusions in prokaryotic cells?

Accepted Answer

They serve as energy and nutrient reserves, reducing osmotic stress.

Question 19

Which of the following is a correct description of the function of teichoic acids in Gram-positive bacteria?

Accepted Answer

They are involved in cell wall structure and can bind to membrane lipids.

Question 20

Which of the following best describes the difference between integral and peripheral membrane proteins?

Accepted Answer

Integral proteins are embedded within the membrane, while peripheral proteins are loosely attached to the membrane surface.

Microbial Cell Structure and Function: Study Notes

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