Carbohydrates are the energy source for biological systems. Carbohydrates are organic compounds containing carbon, hydrogen, and oxygen. Carbohydrates have either an aldehyde or keto functional group with one or more hydroxyl group. Carbohydrates are poly-hydroxy aldehydes or ketones.
Classification of Carbohydrates:
Based on Functional Group – Carbohydrates containing aldehydes are aldoses and keto containing are ketoses.
BASED ON NUMBER OF CARBON ATOMS IN CHAIN (MONOSACCHARIDES) – The first carbohydrate has three carbon atoms.
BASED ON CONFIGURATION – Carbohydrates are given prefix of D or L depending on the positioning of a hydroxyl group attached to the penultimate carbon atom at the other end of the aldehyde or keto group. ‘D’ is assigned if the hydroxyl groups are on the right side of the Fisher projection of the molecular structure and ‘L’ if on the left side.