Question 1

Which of the following best describes the structure and function of the cytoplasmic membrane in prokaryotes?

Accepted Answer

It is a phospholipid bilayer with embedded proteins, acting as a highly selective permeability barrier and site of energy conservation.

Question 2

A bacterium is observed to have a thick peptidoglycan layer, teichoic acids, and no outer membrane. Which type of cell wall does it possess?

Accepted Answer

Gram-positive

Question 3

Which of the following is a key difference between bacterial and archaeal cytoplasmic membranes?

Accepted Answer

Archaeal membranes contain ether linkages and isoprenes, while bacterial membranes contain ester linkages and fatty acids.

Question 4

A researcher isolates a microbe with a cell wall composed of N-acetylglucosamine and N-acetyltalosaminuronic acid. Which group does this organism most likely belong to?

Accepted Answer

Archaea with pseudomurein

Question 5

Which of the following best explains why small cell size is advantageous for prokaryotes?

Accepted Answer

Small cells have a higher surface area-to-volume ratio, which increases nutrient uptake efficiency and growth rate.

Question 6

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

Accepted Answer

Serving as a site for energy conservation

Question 7

A bacterium is resistant to lysozyme and penicillin, and its cell wall lacks peptidoglycan. Which of the following is the most likely explanation?

Accepted Answer

It is an archaeon with an S-layer or pseudomurein.

Question 8

Which of the following best describes the role of the proton motive force in prokaryotic cells?

Accepted Answer

It drives the rotation of flagella and transport of nutrients across the membrane.

Question 9

Which of the following transport systems in prokaryotes involves chemical modification of the transported substance?

Accepted Answer

Group translocation

Question 10

A patient is infected with a bacterium that forms a thick, highly organized capsule. Which of the following is a likely consequence of this structure?

Accepted Answer

Increased resistance to desiccation and phagocytosis

Question 11

Which of the following statements about endospores is correct?

Accepted Answer

Endospores are highly resistant, dormant structures formed by some Gram-positive bacteria.

Question 12

Which of the following best explains the difference in Gram stain reaction between Gram-positive and Gram-negative bacteria?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer that retains the crystal violet-iodine complex after alcohol treatment.

Question 13

A bacterium is observed to move rapidly in a straight line, then suddenly change direction. Which flagellar arrangement and movement pattern does this most likely represent?

Accepted Answer

Peritrichous flagella with run-and-tumble behavior

Question 14

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

Accepted Answer

Presence of phospholipid monolayers formed by tetraether lipids

Question 15

Which of the following best describes the function of fimbriae in bacteria?

Accepted Answer

They enable attachment to surfaces and formation of pellicles.

Question 16

A bacterium is found to contain magnetosomes. What is the most likely function of these structures?

Accepted Answer

Magnetic orientation within the environment

Question 17

Which of the following is a correct statement about the composition of peptidoglycan?

Accepted Answer

It is composed of repeating units of N-acetylglucosamine and N-acetylmuramic acid linked by peptide cross-bridges.

Question 18

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

Accepted Answer

Providing a paracrystalline protein or glycoprotein layer that resists osmotic pressure

Question 19

A bacterium is exposed to a chemical attractant. Which of the following best describes its movement?

Accepted Answer

It exhibits 'run and tumble' behavior, with longer runs toward higher concentrations of the attractant.

Question 20

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

Accepted Answer

Presence of an outer membrane containing lipopolysaccharide (LPS)

Microbial Cell Structure and Function: Cell Morphology, Membranes, and Cell Walls

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