$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$$

Question 1

Which of the following best describes the main structural difference between the cytoplasmic membranes of Bacteria/Eukarya and Archaea?

Accepted Answer

Bacteria/Eukarya have ester linkages of fatty acids to glycerol, while Archaea have ether linkages of phytanyl to glycerol.

Question 2

Which of the following molecules is responsible for strengthening bacterial cytoplasmic membranes, similar to the role of cholesterol in eukaryotes?

Accepted Answer

Hopanoids

Question 3

A researcher isolates a cell with a cytoplasmic membrane containing biphytanyl monolayers. This cell is most likely:

Accepted Answer

An archaeal cell

Question 4

Which of the following is NOT a function of the cytoplasmic membrane?

Accepted Answer

Site of DNA replication

Question 5

Which transport system involves the chemical modification of the transported substance during its passage across the membrane?

Accepted Answer

Group translocation

Question 6

The equation for the hydrolysis of ATP, which powers ABC transporters, is:

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$$

Question 7

Which of the following best explains why Gram-negative bacteria are generally more resistant to antibiotics that target peptidoglycan?

Accepted Answer

They possess an outer membrane that acts as an additional barrier.

Question 8

Which enzyme is found in animal secretions and destroys bacterial cell walls by cleaving $$\beta-1$$,4-glycosidic bonds?

Accepted Answer

Lysozyme

Question 9

A bacterium is found to lack a cell wall but still survives in isotonic solutions. Which genus is it most likely to belong to?

Accepted Answer

Mycoplasma

Question 10

Which of the following is a unique component of the Gram-negative bacterial outer membrane that can act as an endotoxin?

Accepted Answer

Lipid A

Question 11

Which of the following best describes the structure of peptidoglycan?

Accepted Answer

A polymer of N-acetylglucosamine and N-acetylmuramic acid cross-linked by peptides

Question 12

Which of the following cell wall components is found in fungi but not in bacteria or algae?

Accepted Answer

Chitin

Question 13

A scientist is studying a microorganism with a cell wall composed of pseudomurein. Which of the following statements is true?

Accepted Answer

The cell wall contains $$\beta-1$$,3-glycosidic bonds and is lysozyme-insensitive.

Question 14

Which of the following best explains why Mycobacterium species are resistant to desiccation and many antibiotics?

Accepted Answer

They have a cell wall containing hydrophobic mycolic acids.

Question 15

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

Accepted Answer

They bind cations such as $$\mathrm{Ca}^{2+}$$ and $$\mathrm{Mg}^{2+}.$$

Question 16

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

Accepted Answer

It is used to synthesize ATP via ATP synthase.

Question 17

Which of the following cell wall types is most likely to be found in a diatom?

Accepted Answer

Silica ($$\mathrm{SiO}_2) $$plus protein and polysaccharide

Question 18

Which of the following best describes the function of S-layers in Archaea?

Accepted Answer

They serve as a selective sieve and provide structural support.

Question 19

A virus with an envelope derived from the host cell membrane is most likely to:

Accepted Answer

Be sensitive to solvents that disrupt lipid bilayers

Microbial Cell Structure: Cytoplasmic Membranes and Cell Walls

Study Guide - Practice Questions