7. Prokaryotic Cell Structures & Functions

Which is (are) true concerning the cell wall of prokaryotes?

Peptidoglycan is made up of:

The NAG and NAM molecules of peptidoglycan are connected by a:

The glycan chains of adjacent peptidoglycan molecules are connected by:

Answer the following questions using the diagrams provided, which represent cross sections of bacterial cell walls.

a. Which diagram represents a gram-positive bacterium? How can you tell? <IMAGE>

b. Explain how the Gram stain works to distinguish these two types of cell walls.

c. Why does penicillin have no effect on most gram-negative cells?

d. How do essential molecules enter cells through each wall?

e. Which cell wall is toxic to humans?

If you Gram-stained the bacteria that live in the human intestine, you would expect to find mostly

a. gram-positive cocci.

b. gram-negative rods.

c. gram-positive, endospore-forming rods.

d. gram-negative, nitrogen-fixing bacteria.

e. all of the above.

Bacteria cell walls tend to contain:

a. peptidoglycan.

b. lipid bilayers.

c. cholesterol.

d. pseudomurein.

e. flagellin.

Which of the following statements is true?

a. The cell walls of bacteria are composed of peptidoglycan.

b. Peptidoglycan is a fatty acid.

c. Gram-positive bacterial walls have a relatively thin layer of peptidoglycan anchored to the cytoplasmic membrane by teichoic acids.

d. Peptidoglycan is found mainly in the cell walls of fungi, algae, and plants.