Answer
the correct answer is option (a).
Work Step by Step
Proteins are made up of chain of amino acids. Two amino acids link through their amino and carboxyl groups by formation of a peptide bond. Since a protein contains several peptide bonds, it is called a polypeptide. The structure and function of a protein are determined by the type and sequence of amino acids.
Step 2 of 3 A functional group is a group of atoms or bonds within molecules that are responsible for the chemical reactivity of the molecules. Amino acids have the functional groups like amino group, carboxylic group, hydroxyl group, sulfhydryl group. A functional group is not a link between two amino acids. Hence, option (b) is not correct. Quaternary structure is the interaction between two or more polypeptides of a protein. Hence, option (c) is not correct. The ionic bond is formed between two ions of opposite charges. Ionic bonds do not link amino acids. Hence, option (d) is not correct.
Step 3 of 3 A peptide bond occurs when the amino group of one amino acid reacts with carboxyl group of another amino acid to form a bond. Peptide bonds are one of the stable interactions. Hence, the correct answer is option (a).
