Question 1

Which of the following best describes the function of hopanoids in the bacterial plasma membrane?

Accepted Answer

They stabilize the membrane, similar to the role of cholesterol in eukaryotes.

Question 2

A bacterial cell is observed to be 0.8 μm in diameter and 2.5 μm in length. Which of the following statements is most accurate regarding its size?

Accepted Answer

It is within the average size range for bacteria, which is 0.2–1.0 μm wide and 2–8 μm long.

Question 3

Which of the following is NOT a function of the bacterial plasma membrane?

Accepted Answer

Synthesis of peptidoglycan for the cell wall

Question 4

A microbiologist stains a bacterial sample and observes purple, spherical cells arranged in clusters. Which of the following best describes these bacteria?

Accepted Answer

Gram-positive staphylococci

Question 5

Which of the following best explains why cellular organisms with a diameter less than 0.15 μm are unlikely?

Accepted Answer

They cannot contain the minimum number of essential biomolecules for life.

Question 6

Which of the following arrangements describes a chain of rod-shaped bacteria?

Accepted Answer

Streptobacilli

Question 7

A bacterium is observed to have a flexible, spiral-shaped body and moves with a corkscrew motion. Which genus is most likely being observed?

Accepted Answer

Treponema

Question 8

Which of the following statements about the fluid mosaic model of the bacterial plasma membrane is correct?

Accepted Answer

Integral and transmembrane proteins penetrate the membrane and can move laterally.

Question 9

A researcher is studying a bacterial mutant that lacks hopanoids in its plasma membrane. What is the most likely effect on the cell?

Accepted Answer

The membrane will become more fluid and more permeable.

Question 10

Which of the following best describes the amphipathic nature of phospholipids in the bacterial plasma membrane?

Accepted Answer

They have both hydrophilic heads and hydrophobic tails.

Question 11

A bacterial cell is exposed to a detergent that disrupts the plasma membrane. Which of the following is the most likely immediate consequence?

Accepted Answer

The cell will lose cytoplasmic contents due to leakage.

Question 12

Which of the following is a correct match between bacterial shape and example organism?

Accepted Answer

Coccus – Staphylococcus aureus

Question 13

Which of the following best explains why the plasma membrane is described as 'selectively permeable'?

Accepted Answer

It allows some molecules to pass while restricting others.

Question 14

A bacterial cell is found to have a capsule. Which of the following is a likely function of this structure?

Accepted Answer

It protects the cell from phagocytosis.

Question 15

Which of the following best describes the difference between the plasma membranes of bacteria and eukaryotes?

Accepted Answer

Bacterial membranes contain hopanoids, while eukaryotic membranes contain sterols such as cholesterol.

Question 16

A patient is infected with a bacterium that is rod-shaped and forms chains. Which of the following terms best describes this organism?

Accepted Answer

Streptobacillus

Question 17

Which of the following is a function of peripheral proteins in the bacterial plasma membrane?

Accepted Answer

They are involved in cell signaling and enzymatic activity on the membrane surface.

Question 18

A bacterium is observed to have a single flagellum at one end. What is the term for this flagellar arrangement?

Accepted Answer

Monotrichous

Question 19

Which of the following best explains why the plasma membrane is described as 'fluid' in the fluid mosaic model?

Accepted Answer

Phospholipids and proteins can move laterally within the layer.

Question 20

A bacterial cell is exposed to a temperature increase. According to the graph of permeability vs. temperature, what is the expected effect on a membrane lacking cholesterol or hopanoids?

Accepted Answer

Permeability will increase more rapidly with temperature compared to a membrane with cholesterol or hopanoids.

Functional Anatomy of Bacteria: Cell Size, Shape, and Plasma Membrane

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