Question

Which among the following is not an example of a monosaccharide?
A. Erythrose
B. Xylose
C. Glucose
D. All of the above

Answer 1

Hint:- Monosaccharides are a combination of the simplest form of sugar having 1 oxygen atom and 2 hydrogen atoms for each carbon atom present in the molecule and it is the most fundamental unit of carbohydrates. They cannot be hydrolyzed further into simpler chemical compounds. They are generally colourless, water-soluble, and crystalline solids.

Complete Answer:-
Glucose is a general monosaccharide sugar composed of 6 carbon atoms and an aldehyde group. Hence known as an aldohexose. It is naturally occurring found in fruits or parts of plants. It is a source of energy and helps in the regulation of metabolism. Glucose reached into the cells through the bloodstream, so it is known as blood glucose or blood sugar. Glucose is passed from the blood into the cells for energy storage with the help of the Insulin hormone.
Erythrose is a monosaccharide sugar made up of 4 carbon atoms and one aldehyde group. Hence known as tetrose saccharide. It composes the raw material for the production of anthocyanin and lignin. It reduces sugar. Xylose is a monosaccharide and non-nutritive sweetener. It is composed of 5 carbon atoms. Hence known as pentose. It originated from one of the major units of biomass known as hemicellulose. Xylose is a reducing sugar.
Thus, the right option is D.

Note:- To determine the presence of reducing sugar (monosaccharide), we perform the benedict's test. Reducing sugar is those that have free aldehyde and ketone groups. The essential energy-reserve carbohydrate of plants is starch that comprises thousands of straight glucose units. Cellulose also comprises straight glucose units.