Chemistry - Biomolecules Question with Solution | TestHub

A. Proteins are polyamides formed from amino acids.

This statement is CORRECT. Proteins are polymers of amino acids linked by peptide bonds, which are amide linkages.

B. Except glycine, all other amino acids show optical activity.

This statement is CORRECT. Glycine has two hydrogen atoms on its $\alpha$-carbon, making it achiral. All other standard amino acids have four different groups attached to their $\alpha$-carbon, making them chiral and thus optically active.

C. Natural proteins are made up of L-isomers of amino acids.

This statement is CORRECT. The amino acids found in natural proteins are predominantly L-amino acids.

D. —NH₂ and –COOH groups are attached to different carbon atoms in amino acid.

This statement is INCORRECT. In $\alpha$-amino acids, the amino ($—N{H}_2$) group and the carboxyl ($—COOH$) group are both attached to the same carbon atom, known as the $\alpha$-carbon.