CARBOHYDRATES
Introduction
Carbohydrates occur abundantly in living organisms. They are found in all organisms and in almost all parts of the cell.
Meaning
- The word carbohydrate literally means hydrated carbon. They are composed of carbon, hydrogen and oxygen, the ratio of hydrogen and oxygen is the same as in water.
- Their general formula is Cx(H2O)y, where x and y are the whole number from three to many thousands whereas y may be the same or different whole number.
Definition
- Chemically carbohydrates are defined as polyhydroxy aldehydes or ketones or complex substances, which on hydrolysis yield polyhydroxy aldehyde or ketone subunits. (Hydrolysis involves the breakdown of large molecules into smaller ones utilizing water molecules).
Source
The source of carbohydrates are green plants. These are the primary products of photosynthesis. Other compounds of plants are produced from carbohydrates by various chemical changes.
Cellulose of wood, cotton, and paper, starches present in cereals, root tubers, cane sugar and milk sugar are all examples of carbohydrates.
Conjugated Molecules of Carbohydrates
Carbohydrates in cell combine with
- Protein forming glycoproteins
- Lipids forming glycolipids
Glycoproteins and glycolipids have structural role in the extracellular matrix of animals and bacterial cell wall. Both these conjugated molecules are components of biological membranes.
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