Question 1

Which of the following best explains why small prokaryotic cells tend to grow faster than larger cells?

Accepted Answer

They have a higher surface area-to-volume ratio, which supports greater nutrient exchange per unit cell volume.

Question 2

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

Accepted Answer

Hydrocarbons derived from isoprene units attached to glycerol by ether linkages.

Question 3

A bacterium is observed to have a thick peptidoglycan layer and teichoic acids in its cell wall. Which Gram reaction will it show and why?

Accepted Answer

Gram-positive, because the thick peptidoglycan retains the crystal violet-iodine complex after alcohol treatment.

Question 4

Which of the following best describes the function of porins in Gram-negative bacteria?

Accepted Answer

They function as channels for the entrance and exit of solutes across the outer membrane.

Question 5

Which of the following statements about the bacterial endospore is FALSE?

Accepted Answer

Endospores are produced by both Gram-positive and Gram-negative bacteria.

Question 6

Which of the following best explains why lysozyme is effective against most bacterial cell walls but not against archaeal cell walls?

Accepted Answer

Lysozyme targets β-1,4-glycosidic bonds found in peptidoglycan, which are absent in archaeal cell walls.

Question 7

A researcher isolates a microorganism with a cell wall containing N-acetyltalosaminuronic acid and β-1,3 linkages. Which of the following is most likely TRUE about this organism?

Accepted Answer

It is an archaeon with a pseudomurein cell wall.

Question 8

Which of the following is a function of bacterial capsules and slime layers?

Accepted Answer

Protecting cells from dehydration and aiding in immune evasion.

Question 9

Which of the following best describes the energy source for flagellar rotation in Bacteria and Archaea, respectively?

Accepted Answer

Bacteria use the proton motive force, while Archaea use ATP hydrolysis.

Question 10

A bacterium is found to move toward a source of glucose in its environment. Which process is responsible for this behavior?

Accepted Answer

Chemotaxis

Question 11

Which of the following best explains why a lipid monolayer is advantageous for hyperthermophilic Archaea?

Accepted Answer

It is extremely resistant to heat, preventing membrane dissociation at high temperatures.

Question 12

Which of the following is TRUE regarding group translocation in prokaryotic cells?

Accepted Answer

The transported substance is chemically modified during transport.

Question 13

Which of the following structures is most directly responsible for the selective permeability of the cytoplasmic membrane?

Accepted Answer

Phospholipid bilayer with embedded proteins

Question 14

A bacterium with peritrichous flagella is most likely to exhibit which type of movement?

Accepted Answer

Slow, straight-line movement with frequent changes in direction

Question 15

Which of the following is a correct formula for the surface area to volume ratio of a spherical cell with radius $$r$$?

Accepted Answer

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

Question 16

Which of the following is a major component of the outer membrane of Gram-negative bacteria that is NOT found in Gram-positive bacteria?

Accepted Answer

Lipopolysaccharide (LPS)

Question 17

Which of the following best describes the role of small acid-soluble spore proteins (SASPs) in bacterial endospores?

Accepted Answer

They bind tightly to DNA, protecting it from damage and serving as a carbon and energy source during germination.

Question 18

Which of the following is a distinguishing feature of S-layers in Archaea?

Accepted Answer

They are formed from interlocking layers of protein or glycoprotein that create a paracrystalline structure.

Question 19

Which of the following best explains why open ocean environments tend to contain very small prokaryotic cells?

Accepted Answer

Small cells have a higher surface area-to-volume ratio, allowing for more efficient nutrient uptake in nutrient-poor environments.

Microbial Cell Structure and Function: Comprehensive Study Notes

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