Tuesday 25 August 2015

Function of Cell Membrane

These are the important functions of cell membrane.
1) The cell membrane cause compartmentalisation. As plasma membranes they separates the cell from external environment.
2) Plasma membrane protect the cell from injury.
3) The plasma membrane allow the flow of materials and information between one cell and another, the cell membrane makes metabolism possible.
4) Plasma membranes of the adjacent cells form various types of junctions for keeping the cells together.
5) plasma membranes as well as other membranes of the organelles have selective permeability, they allow only selected substances to pass inwardly. The membranes are impermeable to others.
6) Membranes have carrier proteins for active transport.
It helps certain cells in movement by forming psudopodia as in Amoeba and leucocytes.
7) Substances attached to cell membrane determine antigen specificity.
8) In nerve cells the cell membrane takes part in transmission of impulses.
9) Membrane infolds are used for bulk intake of materials by endocytosis.
10) Cell membranes contain enzymes for performing certain reactions on their surfaces. e.g. ATPase
11) As microvilli the membrane becomes specialized for the absorption of substances.

Different types of membranes:-
a) Permeable membrane :- These membranes allow all types of solute, solvent and ions through them e.g. cellulose wall of cells.
b) Impermeable membrane :- These types of membranes does not allow the diffusion of both solute and solvent molecules. e.g. heavily cutinised cell walls in plants.
c) Semipermeable membranes :- These types of membranes allow diffusion of solvent molecules but do not allow the passage of solute particles. e.g. parchment paper.
d) Differentially permeable membranes :- These are also called selectively permeable membranes. These type of mmbranes allow only selected solute molecules and slovent molecules to pass through them. e.g. plasma membrane.



 

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