Question

Hexoses and pentoses are

• A. disaccharides
• B. monosaccharides
• C. polysaccharides
• D. oligosaccharides

Answer 1

Answer: (B)

Those sugars which contain $2,3,5,6$ carbon atoms are known as monosaccharides.
Hexoses and pentoses have six and five carbon atom respectively so these are monosaccharides. Monosaccharides are the simplest carbohydrates which cannot be hydrolysed into simpler compounds eg, ribose
$C_5{H}_{10}{O}_5$ , glucose $C_6{H}_{12}{O}_6$ , etc.
Disaccharides give two molecules of monosaccharides on hydrolysis, example sucrose, lactose maltose. All these have molecular formula. $C_{12}{H}_{22}{O}_{11}$
Polysaccharides These are polymeric and give a large number of monosaccharide on hydrolysis eg, starch $(C_6{H}_{10}{O}_5{)}_n$
Oligosaccharides These are classified into disaccharides, trisaccharides, tetrasaccharides etc.