Cell Membrane Function & Type

Functions

• Transport of the molecules. The membrane is selectively permeable to some molecules present on either side of it.
• Due to the fluid nature, the plasma membrane can help in cell growth, formation of intercellular junctions, secretion, endocytosis, cell division etc.

Types of Transport

• 1.Passive transport: It is the movement of molecules across the membrane along the concentration gradient (i.e., from higher concentration to the lower) without the expenditure of energy. It is 2 types:
  a. Simple diffusion: It is the movement of neutral solutes across the membrane.
  b. Osmosis: It is the movement of water by diffusion across the membrane.
  As the polar molecules cannot pass through the non-polar lipid bilayer, they require a carrier protein of the membrane to facilitate their transport.
  2.Active transport: It is the movement of molecules across the membrane against the concentration gradient (i.e. from lower to the higher concentration) with the expenditure of energy (ATP is utilized). E.g. Na+/K+pump.