Match List-I with List-II
|
List-I |
List-II |
|
(A) Denaturation |
(I) Sequence of amino acids in a protein |
|
(B) Primary structure of protein |
(II) \(\alpha \)-Helix and \(\beta \)-pleated sheets |
|
(C) Quaternary structure of protein |
(III) \(2^o\) and \(3^o\) structures gets destroyed |
|
(D) Secondary structure of protein |
(IV) The spatial arrangement of subunits (containing 2 or more polypeptide chain) with respect to each other. |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
Protein structure is described at four levels: the amino acid sequence (primary), the local folding of the chain (secondary), the folding of the whole chain (tertiary), and the arrangement of several chains (quaternary).
(A) Denaturation — This matches (III) 2° and 3° structures gets destroyed. Heat or a change in pH breaks the hydrogen bonds; the helices uncoil and the protein loses its biological activity, while the primary structure stays intact (e.g. coagulation of egg white on boiling).
(B) Primary structure of protein — This matches (I) Sequence of amino acids in a protein. Any change in this sequence gives a different protein.
(C) Quaternary structure of protein — This matches (IV) The spatial arrangement of subunits (containing 2 or more polypeptide chain) with respect to each other, as in haemoglobin with four subunits.
(D) Secondary structure of protein — This matches (II) α-Helix and β-pleated sheets, the two shapes in which the chain is held by hydrogen bonds between >C=O and –NH– groups.
Shortcut: (A)-(III) leaves Options (2) and (3); (B)-(I) then leaves only Option (2).