JEE Main · 2023 · 12 Apr 2023 · Shift 1 · Biomolecules

The tetrapeptide alanyl-glycyl-phenylalanyl-isoleucine is joined by three peptide (amide) linkages and carries one terminal carboxyl group. Each of the three amide carbonyl carbons and the terminal carboxyl carbon is $s{p}^2$ hybridised, which gives four $s{p}^2$ carbons. The benzene ring of the phenylalanine residue contributes six more $s{p}^2$ carbons. Adding these, $4+6$, the number of $s{p}^2$ hybridised carbons is 10.