STORED ENERGY AND STRUCTURAL SUPPORT
Polyhydroxy aldehyde or ketones are called carbohydrate. Carbohydrates are major source of energy for animals. Most animal cells have chemical machinery. It breaks down the energy rich carbon hydrogen (C-H) bonds. Simple carbohydrates (e.g. monosaccharide) are composed of atoms of carbon, hyrirnnen and oxvaen. Carbohydrates are classified according to their molecular
he simplest types with short carbon chains are monosaccharide or ugars. Monosaccharide tastes sweet. Monosaccharides are the building blocks f more complex carbohydrate molecules. Four common monosaccharides in nimals are glucose, fructose, glyceraldehydes, and dihydroxyacetone.
H 0 H1
H – Ci -OH
H – C OH C=O
H OH – C H OH -C H
\ I I
C H – C – OH H – C OH H – C – OH
H C OH CO H —C —OH HC-OH
I I I
H C OH H —C –OH H —C —OH H — C —OH
I I I I
(: H •
H H H
(i) Sucrose (table sugar): It is a disaccharide formed by linking a molecule of glucose to a molecule of fructose.
(ii) Lactose: A glucose molecule bonds to another monosaccharide, galactose and it forms disaccharide lactose (commonly called milk sugar).
(iii) Maltose: It is formed by the joining of glucose subunits. It gives beer seeds a sweet taste. Beer brewers ferment barley into alcohol.
Many monosaccharides joined to form polysaccharides.
(i) Glycogen: It is a major storage compound in animals. The number of glucose units within the glycogen molecule varies. Thus it is symbolized by the formula (C6H1005),, . The n is equal to the number of glucose units in the molecule.
(ii) Chitin: It is a major component of the exoskeleton of insects and crustaceans.
(iii) Starch: It is a storage form of carbohydrate in plants) recruitment of the cell wall of plants