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?

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?

Starch is readily metabolized by many cells, but a starch molecule is too large to cross the plasma membrane. How does a cell obtain the glucose molecules from a starch polymer? How does the cell transport these glucose molecules across the plasma membrane?

Which of the following is false about fimbriae?

a. They are composed of protein.

b. They may be used for attachment.

c. They are found on gram-negative cells.

d. They are composed of pilin.

e. They may be used for motility.

Compare and contrast the following:

a. Simple diffusion and facilitated diffusion

b. Active transport and facilitated diffusion

c. Active transport and group translocation

Which of the following statements best describes what happens to a cell exposed to polymyxins that destroy phospholipids?

a. In an isotonic solution, nothing will happen.

b. In a hypotonic solution, the cell will lyse.

c. Water will move into the cell.

d. Intracellular contents will leak from the cell.

e. Any of the above might happen.

Which of the following pairs is mismatched?

a. Metachromatic granules—stored phosphates

b. Polysaccharide granules—stored starch

c. Lipid inclusions—poly-β-hydroxybutyric acid

d. Sulfur granules—energy reserve

e. Ribosomes—protein storage

Which of the following pairs is mismatched?

a. Glycocalyx—adherence

b. Pili—reproduction

c. Cell wall—toxin

d. Cell wall—protection

e. Plasma membrane—transport