OSMOSIS

PHYSIO -CHEMICAL NATURE OF PLASMA MEMBRANE

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.

OSMOSIS

The movement of solvent molecules from the region of higher concentration to the region of lower concentration through semi permeable membrane is called osmosis. Demonstration A thistle funnel is filled with a concentrated solution of sucrose. Its mouth is closed with a rubber membrane.