Carbohydrates

Introduction

Carbohydrates are substances which contains the elements carbon, hydrogen and oxygen and have the general formula C_x(H₂O)_y, where x and y are variable numbers; their name (hydrate of carbon) is derived from the fact that hydrogen and oxygen are present in the same proportions as in water, namely 2 hydrogen atoms to one oxygen atom. In addition, they have the following properties:

• All are aldehydes or ketones

• All contain several hydroxyl groups

These groups determine their chemistry. For example, aldehydes are very easily oxidized and hence are powerful reducing agents.

Carbohydrates are divided into 3 main classes monosaccharides, disaccharides and polysaccharides.

They are polyhydroxy aldehydes or polyhydroxy ketones or substances that yield these compounds when hydrolyzed.

They provide an essential base for the world’s food chain. Plants use light energy to convert carbon dioxide and water into carbohydrates. Herbivores eat these plants and are, in turn, eaten by carnivores. The energy originally present in the plant carbohydrate is transferred up the food chain.