#1: Cell membrane disruption
The first pathway involves the disruption of the bacterial cell membrane. Bacterial cell membranes consist of a phospholipid bilayer, which acts as a selective barrier to allow the passage of small molecules while excluding large ones. Antibiotics such as penicillin and cephalosporins work by inhibiting the synthesis of a critical component of the bacterial cell wall, called peptidoglycan. Without a functional peptidoglycan layer, the bacterial cell membrane is unable to maintain its structural integrity and eventually ruptures, leading to cell death.