Each of the following statements concerning the mechanism of action of antibacterial drugs is correct EXCEPT:

  •  Erythromycin is a bacteriostatic drug that inhibits protein synthesis by blocking translocation of the polypeptide.
  •  Aminoglycosides are bacteriostatic drugs that inhibit protein synthesis by activating ribonuclease, which degrades mRNA.
  •  Cephalosporins are bactericidal drugs that inhibit the transpeptidase reaction and prevent cell wall synthesis.
  •  Tetracyclines are bacteriostatic drugs that inhibit protein synthesis by blocking tRNA binding.