Answer
the correct answer is option (d)
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. Proteins have different levels of structure. The functions of most of the proteins are due to these different levels of structural hierarchy.
Step 2 of 3 A primary structure of a protein defines the sequential arrangement of the amino acids. Hence, option (a) is not correct. The secondary structure of a protein defines the folding of a polypeptide chain and the intermolecular interactions that enable the folding. Hence, option (b) is not correct. The tertiary structure of a polypeptide chain defines the folding of individual regions of the polypeptide into specific three-dimensional structures. Hence, option (c) is not correct.
Step 3 of 3 The quaternary structure of proteins defines the interactions between individual polypeptide chains of a protein. Quaternary structure is applicable to proteins with more than one polypeptide chains, for example, hemoglobin. Hence, the correct answer is option (d)
