Carbohydrates
Carbohydrates are very much essential to life and occur in all plants and
animals. Through photosynthesis, plants convert CO2 and H2O into
carbohydrates mainly cellulose, starch and sugars. Cellulose is the building
block of rigid cell walls and woody tissues in plants. Starch is the storage form
of carbohydrates for later use as food or energy source. Some plants (cane and
sugar beets) produce sucrose (table sugar). Glucose is an essential component
of blood. Two other sugars ribose and 2-dexoyribose are components of RNA
and DNA. Other carbohydrates are important components of coenzymes,
antibiotics, cartilage, bacterial cell wall and mammalian cell membranes. Thus
carbohydrates provide us all the three basic needs like food, cloth and shelter.
All carbohydrates contain number of hydroxyl groups and carbonyl group
(aldehyde or ketone). Thus carbohydrates are defined as “Polyhydroxy aldehydes
or polyhydroxy ketones and other compounds which give these on hydrolysis are
called carbohydrates”. |