Explain using the lock-and-key model why pepsin can hydrolyze peptide bonds in proteins but not the glycosidic bonds in starch.

Pepsin lacks the necessary cofactors to hydrolyze glycosidic bonds in starch.

Pepsin's active site is specifically shaped to bind to peptide bonds in proteins.

Pepsin's active site matches the structure of starch.

Pepsin is only active in an acidic environment.