Match the LIST-I with LIST-II.
| LIST-I Biomolecule | LIST-II Types of bonds/structural features |
| A. Nucleic acids | I. Glycosidic bonds between C-1 and C-4 of two β-D-glucose units. |
| B. Cellulose | II. Hydrogen bonding, van der Waals and Disulphide bonds |
| C. Tertiary structure of proteins | III. Glycosidic bonds between C-1 and C-4 of two α-D-glucose units. |
| D. Amylose | IV. Phosphodiester bonds |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → A-IV, B-I, C-II, D-III
In a biopolymer, the monomer units are joined by one type of covalent link: glycosidic links in polysaccharides, phosphodiester links in nucleic acids and peptide links in proteins. The higher levels of protein structure are held by weaker side-chain interactions instead.
A. Nucleic acids — This matches IV. Phosphodiester bonds. Nucleotides are joined by a phosphate group that links C-5′ of one pentose sugar to C-3′ of the next.
B. Cellulose — This matches I. Glycosidic bonds between C-1 and C-4 of two β-D-glucose units. Cellulose is a straight chain of β-D-glucose units joined by C1–C4 glycosidic links. Humans lack the enzyme to break these β links, so they cannot digest cellulose.
C. Tertiary structure of proteins — This matches II. Hydrogen bonding, van der Waals and Disulphide bonds. The folding of the whole chain is held in place by these side-chain forces, together with electrostatic attractions.
D. Amylose — This matches III. Glycosidic bonds between C-1 and C-4 of two α-D-glucose units. Amylose is the water-soluble, unbranched part of starch (15–20%), a long chain of α-D-glucose units joined by C1–C4 glycosidic links.
Shortcut: The pair A–IV appears in Options (1) and (4), and B–I then leaves only Option (4).