Penicillins work by destroying this part of the bacterial cell.

Penicillins work by destroying this part of the bacterial cell.

• A. Cell wall
• B. Cytoplasmic membrane
• C. Nucleus
• D. Ribosome

Answer: (A)

Penicillins disrupt bacterial growth by targeting the cell wall. They bind to penicillin-binding proteins that normally cross-link peptidoglycan strands, which is essential for strengthening the wall during growth. When this cross-linking is blocked, the cell wall becomes weak, osmotic pressure causes the wall to rupture, and the bacterium dies. The nucleus isn’t present in bacteria, so it isn’t a target; the cytoplasmic membrane isn’t the primary site affected by penicillins, and ribosomes are the targets of other antibiotic classes. Thus, the structure most directly destroyed by penicillins is the cell wall.

Penicillins disrupt bacterial growth by targeting the cell wall. They bind to penicillin-binding proteins that normally cross-link peptidoglycan strands, which is essential for strengthening the wall during growth. When this cross-linking is blocked, the cell wall becomes weak, osmotic pressure causes the wall to rupture, and the bacterium dies. The nucleus isn’t present in bacteria, so it isn’t a target; the cytoplasmic membrane isn’t the primary site affected by penicillins, and ribosomes are the targets of other antibiotic classes. Thus, the structure most directly destroyed by penicillins is the cell wall.