Match List-I with List-II
|
List-I Structure of Protein |
List-II Function |
|
(A) Primary Structure |
(I) Gives rise to Fibrous and Globular Proteins |
|
(B) Secondary structure |
(II) Sequence of amino acid |
|
(C) Tertiary Structure |
(III) Shape of polypeptide Chain |
|
(D) Quaternary Structure |
(IV) Spatial arrangement of sub-units |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A)-(II), (B)-(III), (C)-(I), (D)-(IV)
The structure of a protein is described at four levels, each built on the one before: the order of the amino acids, the local shape of the chain, the folding of the whole chain, and the packing of several chains together.
(A) Primary Structure — This matches (II) Sequence of amino acid. The primary structure is the order in which the amino acids are joined by peptide bonds in the chain; any change in this sequence gives a different protein.
(B) Secondary structure — This matches (III) Shape of polypeptide Chain. It is the shape in which the long chain exists, the α-helix or the β-pleated sheet, held by hydrogen bonds between the C=O and N–H groups of peptide bonds.
(C) Tertiary Structure — This matches (I) Gives rise to Fibrous and Globular Proteins. The further folding of the whole chain, held by hydrogen bonds, disulphide links, van der Waals and electrostatic forces, gives the two molecular shapes, fibrous and globular.
(D) Quaternary Structure — This matches (IV) Spatial arrangement of sub-units. Proteins made of two or more polypeptide chains (sub-units), such as haemoglobin, have a quaternary structure: the way these sub-units are arranged with respect to each other.
Shortcut: (A)-(II) appears only in Option (1).
NCERT (2026-27 edition):
Structure of Proteins – “… (i) Primary structure of proteins: … it is this sequence of amino acids that is said to be the primary structure of that protein.
(ii) Secondary structure of proteins: The secondary structure of protein refers to the shape in which a long polypeptide chain can exist. …
(iii) Tertiary structure of proteins: The tertiary structure of proteins represents overall folding of the polypeptide chains i.e., further folding of the secondary structure. It gives rise to two major molecular shapes viz. fibrous and globular. …
(iv) Quaternary structure of proteins: Some of the proteins are composed of two or more polypeptide chains referred to as sub-units. The spatial arrangement of these subunits with respect to each other is known as quaternary structure.”