Which one of the following statements statements is correct?

Options

A. starch is a polymer of `alpha`-glucose
B. Amylose is a component of cellulose
C. Proteins are composed of only one type of amino acid
D. In cyclic structure of fructose, there are only three carbons and one oxygen atom.

Answer

A

Explanation

Cellulose, the fibrous substance that forms the structural material in grasses, leaves and stems, consists of several thousand `beta-` glucose molecules joined together by 1, 4 links to form an immense polysaccharide.
Starch, link cellulose is also a polymer of glucose. Unlike cellulose, though, starch is eidble. Indeed, the starch in such vegetables as beans, rice and potatoes is an essential part of the human diet. Structurally, starch differs from cellulose in that it contains `alpha`-rather than `beta`- glucose units. Starch is also more structurally complex than cellulose and is of two types: amylose and amylopectin.