Match the LIST-I with LIST-II.
| LIST-I Carbohydrate | LIST-II Glycosidic linkage between |
| A. Sucrose | I. C1 of α-D-glucose and C2 of β-D-fructose |
| B. Maltose | II. C1 of β-D-galactose and C4 of β-D-glucose |
| C. Lactose | III. C1 of β-D-glucose and C4 of β-D-glucose |
| D. Cellulose | IV. C1 of α-D-glucose and C4 of α-D-glucose |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → A-I, B-IV, C-II, D-III
In disaccharides and polysaccharides, monosaccharide units are joined by a glycosidic linkage, an oxide link formed between two units with loss of water. Each carbohydrate is identified by which units are joined, which carbons, and whether the linkage is α or β:
(A) Sucrose — This matches (I) C1 of α-D-glucose and C2 of β-D-fructose. Both reducing groups are used in the link, so sucrose is a non-reducing sugar.
(B) Maltose — This matches (IV) C1 of α-D-glucose and C4 of α-D-glucose. It is made of two α-D-glucose units, and the free C1 of the second unit makes it a reducing sugar.
(C) Lactose — This matches (II) C1 of β-D-galactose and C4 of β-D-glucose. Lactose is milk sugar, made of galactose and glucose.
(D) Cellulose — This matches (III) C1 of β-D-glucose and C4 of β-D-glucose. It is a straight chain polymer of β-D-glucose units.
Shortcut: All options have (A)–(I). (B)–(IV) appears in Options (3) and (4), and (C)–(II) then leaves only Option (3).