The plasma membrane surrounds the cell. Chemically plasma membrane is composed of: (a) Protein: 60 to 80% (b) Phospholipids: 20 to 40% (e) Cholesterol in small amount (d) Carbohydiutes in small amount Different models were put forward about the physiochemical nature of plasma membrane.
Carbohydrates are polyhydroxy aldehydes or ketones. Carbohydrates are sugars and their polymers. They are composed of carbon, hydrogen and oxygen. The word carbohydrates literally mean hydrated carbons. The ratio of hydrogen and oxygen is the same, as in water, i.e. Their general formula is
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