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*Penicillin interferes with bacterial cell growth by which of the following mech

ID: 194248 • Letter: #

Question

*Penicillin interferes with bacterial cell growth by which of the following mechanisms by

a. inhibiting the formation of short polypeptide crosslinks between strands of polysaccharide in peptidoglycan that are made of repeated units of N-acetylglucosamine (NAG) linked to N-acetylmuramic acid (NAM)

b. hydrolyzing strands of polysaccharide in peptidoglycan that are made of repeated units of N-acetylglucosamine (NAG) linked to N-acetylmuramic acid (NAM)

c. disrupting the integrity of the cytoplasmic membrane and preventing the formation of a proton gradient that is required for ATP production

d. binding to proteins that are required for binary fission of actively growing bacterial cells

*Bacterial cells reproduce by binary fission, which results in exponential growth of the population. If the size of a bacterial population at time zero (t0) is 20 cells and the generation time is 30 minutes, how many cells will be in the population after 3 hours of growth?
a. It is not possible to calculate the number with the information provided

b. 1280 cells

c. 2560 cells

d. 5120 cells

e. 64 million cells

*The formation of endospores is an example of cell differentiation in bacteria. Which of the following are true statements about endospores?

a. all species of Gram-positive bacteria can undergo cell differentiation to produce endospores

b. the formation of endospores occurs through an asymmetrical cell division process that produces a forespore and ultimately an endospore

c. bacterial spores are resistant to heat, but not desiccation

d. these are all true statements

*The most widely used solidifying agent used in bacteriological growth media is:

a. gelatin

b. xanthan gum

c. agar

d. epoxy resin

Explanation / Answer

correct answers are provided below in sequential manner

a. inhibiting the formation of short polypeptide crosslinks between strands of polysaccharide in peptidoglycan that are made of repeated units of N-acetylglucosamine (NAG) linked to N-acetylmuramic acid (NAM)

b. 1280 cells

c. agar