JEE Main · 2021 · 27 Jul 2021 · Shift 2 · Biomolecules

Compound A gives D-Galactose and D-Glucose on hydrolysis. The compound A is:

(A)Amylose
(B)Sucrose
(C)Maltose
(D)Lactose✓ Correct

Answer: (D)

Solution

Lactose is the disaccharide in which D-galactose is joined to D-glucose through a

β

-glycosidic link between

C_{1}

of galactose and

C_{4}

of glucose, so breaking that link on hydrolysis releases exactly these two monosaccharides. Maltose is built from two glucose units, sucrose from glucose and fructose, and amylose is a polymer of glucose alone, so none of them can supply galactose. The compound A is lactose.

JEE Main · 2021 · 27 Jul 2021 · Shift 2 · Single correct option

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