What is the mechanism of action of penicillins?

• A. Inhibits protein synthesis
• B. Prevents DNA replication
• C. Interferes with synthesis of bacterial cell walls
• D. Inhibits folic acid synthesis

Answer: (C)

The mechanism of action of penicillins is centered around their ability to interfere with the synthesis of bacterial cell walls. Penicillins are a class of antibiotics that target the enzymes responsible for forming cross-links in the peptidoglycan layer, which is crucial for maintaining the structural integrity of bacterial cell walls. By inhibiting these enzymes, penicillins compromise the strength and stability of the cell wall, ultimately leading to cell lysis and death, particularly in actively dividing bacteria.

This action is highly effective against a range of Gram-positive bacteria, which possess a thick peptidoglycan layer. The specificity of penicillins toward bacterial cells, due to their unique cell wall composition, makes them an important group of antibiotics for treating various bacterial infections. While other antibiotics work by inhibiting protein synthesis, preventing DNA replication, or inhibiting folic acid synthesis, these mechanisms do not apply to the action of penicillins, which are fundamentally about disrupting cell wall synthesis.