1) Carbohydrates Constituents of carbohydrates are “ Carbon , Hydrogen and Oxygen ". The general formulae of carbohydrates is cx (H2O) y. In carbohydrates always Hydrogen and Oxygen are in the ratio 2:1. They are made of saccharide units (literally sugar) - a prefix (mono-, di-, poly-) denotes how many units. Carbohydrates are classified as Monosaccharides, Disaccharides and polysaccharides.