Penicillin is effective against bacteria because it inhibits their wall formation.

The given statement is True

Penicillins and other antibiotics in the beta-lactam family contain a characteristic four-membered beta-lactam ring. Penicillin kills bacteria through binding of the beta-lactam ring to DD-transpeptidase, inhibiting its cross-linking activity and preventing new cell wall formation. Without a cell wall, a bacterial cell is vulnerable to outside water and molecular pressures, and quickly dies. Since human cells do not contain a cell wall, penicillin treatment results in bacterial cell death without affecting human cells.