South Dakota Medication Aide Practice Test

Penicillins primarily kill bacteria by interfering with bacterial cell wall synthesis. This class of antibiotics functions by binding to specific proteins known as penicillin-binding proteins (PBPs) located on the bacterial cell membrane. When penicillins attach to these proteins, they inhibit the formation of peptidoglycan, which is an essential component of the bacterial cell wall.

Without a proper cell wall, bacteria cannot maintain their structural integrity, leading to lysis and eventual death, especially in hypotonic environments where the osmotic pressure is higher outside the bacterial cell. This mechanism makes penicillin effective primarily against Gram-positive bacteria, which have a thick peptidoglycan layer.

While the other choices represent various mechanisms by which different classes of antibiotics operate, none apply to penicillins—disrupting metabolic pathways is typical of sulfonamides, inhibiting protein synthesis usually describes tetracyclines or macrolides, and targeting cell membranes is characteristic of drugs like polymyxins. Understanding the specific action of penicillins is crucial for effectively applying this knowledge in medication administration and infection control.