Answer:-
The cytoplasm is bounded on the outside by a thin, delicate and flexible membrane known as cell membrane or plasma membrane (also called sarcolemma in case of muscle fibre cell and neurolemma in nerve cell). The main functions of cell membrane are-
1) Cell membrane gives definite shape to the cell and provides mechanical support.
2) Different muco/glyco-proteins of membranes of RBCs constitute the blood groups.
3) Membrane bound phospholipase C takes part in calcium-phosphatidyl-inositol system.
4) EXOCYTOSIS: Cell membrane takes part in secretion of secretory materials like digestive enzymes, hormones, plasma proteins, immunoglobulins, etc. and excretion of waste products out side the cell.
5) Cell membrane possesses various plasma membrane bound receptors for the physiological actions of various hormones, neurotransmitters and drugs.
