Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug?
a. the drugs also work against dna gyrase.
b. they are less expensive that other chemotherapeutic agents.
c. bacteria are especially sensitive to these compounds.
d. humans and other animal hosts lack peptidoglycan cell walls.

The correct answer is d. Humans and other animal hosts lack peptidoglycan cell walls.

Explanation:

Bacterial cell wall is mainly made up of peptidoglycan layer which protects their internal structure of cells from the harsh external environment. Most of the bacteria are pathogenic to humans and chemotherapeutic agents are present in the market that kill them by destroying their cell wall.

Animal and human cells do not have any cell wall outside their cell membrane so these chemotherapeutic agents do not harm human or animal cells and are very selective for bacteria that contain peptidoglycan cell wall.

They can target the peptidoglycan in two ways 1. inhibit the formation of new peptidoglycan like penicillin or 2. By destroying the old peptidoglycan layer like lysozyme.  

Therefore the right answer is d. Humans and other animal hosts lack peptidoglycan cell walls.

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