Which organism is least affected by antibiotics that block cell wall synthesis?

The organism that is least affected by antibiotics that block cell wall synthesis is animals. This is because animal cells do not possess a cell wall; instead, they have only a plasma membrane that regulates the movement of substances in and out of the cell.

Antibiotics that target cell wall synthesis, such as penicillin, work by inhibiting the formation of peptidoglycan, a critical component of bacterial cell walls. Since animal cells lack this structure, they are not impacted by these antibiotics.

In contrast, bacteria, plants, and fungi have cell walls composed of peptidoglycan, cellulose, and chitin, respectively. Antibiotics that disrupt cell wall synthesis can effectively combat bacterial infections by weakening or destroying bacterial cells. Thus, while these organisms can be significantly affected by the action of such antibiotics, animals remain unaffected due to their unique cellular architecture.