Question 1

Which of the following best describes the main function of the cytoplasmic membrane in bacterial cells?

Accepted Answer

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

Question 2

Which structural feature distinguishes archaeal cytoplasmic membranes from those of bacteria and eukaryotes?

Accepted Answer

Presence of isoprenoid chains and ether linkages in phospholipids

Question 3

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

Accepted Answer

Gram-positive

Question 4

Which of the following transport systems chemically modifies the substance being transported across the bacterial membrane?

Accepted Answer

Group translocation

Question 5

Why are ABC transporters particularly advantageous for bacteria living in nutrient-poor environments?

Accepted Answer

They have high substrate affinity due to substrate-binding proteins.

Question 6

Which component of the Gram-negative bacterial cell envelope is responsible for its toxicity in humans?

Accepted Answer

Lipid A of lipopolysaccharide (LPS)

Question 7

A scientist treats a bacterial culture with lysozyme and observes cell lysis. Which structural feature is most likely being targeted?

Accepted Answer

β-1,4 glycosidic bonds in peptidoglycan

Question 8

Which of the following statements about endospores is FALSE?

Accepted Answer

They are a form of active cell division under nutrient-rich conditions.

Question 9

Which cell surface structure is primarily responsible for bacterial attachment to surfaces and biofilm formation?

Accepted Answer

Capsules and slime layers

Question 10

A bacterium is observed to move toward a capillary tube containing glucose. This behavior is best described as:

Accepted Answer

Chemotaxis

Question 11

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

Accepted Answer

Archaea lack peptidoglycan in their cell walls.

Question 12

Which of the following is a unique feature of the S-layer found in some Archaea and Bacteria?

Accepted Answer

It forms a paracrystalline protein or glycoprotein layer.

Question 13

Which of the following is NOT a function of small acid-soluble spore proteins (SASPs) in bacterial endospores?

Accepted Answer

Facilitating motility in liquid environments

Question 14

Which of the following best describes the arrangement of flagella in a peritrichous bacterium?

Accepted Answer

Flagella distributed over the entire cell surface

Question 15

Which of the following is a key difference between bacterial and eukaryotic flagella?

Accepted Answer

Eukaryotic flagella move by a whiplike motion powered by ATP.

Question 16

A mutation in a bacterium prevents the formation of porins. Which process would be most directly affected?

Accepted Answer

Transport of small molecules across the outer membrane

Question 17

Which of the following inclusions allows bacteria to orient and migrate along magnetic field lines?

Accepted Answer

Magnetosomes

Question 18

Which of the following statements about the endosymbiotic hypothesis is TRUE?

Accepted Answer

Mitochondria and chloroplasts descended from bacterial cells that formed symbiotic relationships with early eukaryotes.

Question 19

Which of the following is a function of the eukaryotic cytoskeleton?

Accepted Answer

Maintaining cell shape and facilitating motility

Question 20

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

Accepted Answer

Alternating runs and tumbles, with runs biased toward attractant

Microbial Cell Structure and Function: Study Notes for Microbiology Students

Study Guide - Practice Questions

Study Guide - Flashcards