Which of the following structures represents the peptide chain?

Options

A. `-underset(|)overset(|)(C)-overset(H)overset(|)(N)-underset(|)overset(|)(C)-underset(|)overset(|)(C)-overset(O)overset(||)(C)-underset(H)underset(|)(N)-underset(|)overset(|)(C)-underset(|)overset(|)(C)-overset(H)overset(|)(N)-underset O underset(||)(C)-underset(|)overset(|)C-underset(|)overset(|)C-`
B. `-overset(H)overset(|)N-underset(O)underset(||)C-underset(H)underset(|)C-underset(|)overset(|)C-NH-overset(O)overset(||)C-NH-`
C. `-overset(H)overset(|)N-underset(O)underset(||)C-underset(|)overset(|)C-underset(|)overset(|)C-underset(|)overset(|)C-overset(H)overset(|)N-underset(|)overset(|)C-underset(|)overset(|)C-underset(|)overset(|)C-`
D. `-oversetHoverset(|)N-underset(|)overset(|)C-undersetOunderset(||)C-overset(H)overset(|)N-underset(|)overset(|)C-underset(O)underset(||)C-overset(H)overset(|)N-underset(|)overset(|)C-underset(O)underset(||)C-overset(H)overset(|)N-underset(|)overset(|)C-`

Answer

D

Explanation

The peptide linkage `(-NH-CO-)` is formed by the condensation of amino acid molecules.
`HNH-underset(R)underset(|)CH-underset(O)underset(||)C-OH + H . NH-underset(R)underset(|)CH-underset(O)underset(||)C-OH`
`overset(-H_(2)O)rarr-HN-underset(R)underset(|)CH-underset(O)underset(||)C-NH- underset(R)underset(|)CH-underset(O)underset(||)C-`
Hence, following structure represents the peptide chain
`-overset(H)overset(|)N-underset (|)overset(|)C-underset(O)underset(||)C-overset(H)overset(|)N-underset(|)overset(|)C-underset(O)underset(||)C-overset(H)overset(|)N-underset(|)overset(|)C-overset(O)overset(||)C-`