Cell Membrane

• Cell membrane is also known as plasma membrane.
• Cell membrane (plasma membrane) transport the molecules across it.
• It is selective permeable (selective permeable > semi permeable).
• It is a biological membrane that separates the all inside cells from outside world or environment.
• It is (cell membrane) composed of lipids that are arranged in a bilayer (lipid bilayer).
• Within the cell membrane, lipids arrange with polar head towards the outer side & the tails (hydrophobic tails) towards the inner part. This ensures that the non polar tail of saturated hydrocarbons is protected from the aqueous environment.
• Cell membrane possess lipid, protein & carbohydrate (ratio of lipid & protein varies accordingly in different cell types).
• In humans, erythrocyte membrane has approx 52% protein & 40% lipids.
• Membrane protein classified on the basis of ease of extraction as integral protein & peripheral protein.
• The integral protein are partially or totally buried in the cell membrane.
• Peripheral protein lie on the surface of membrane.

"Spectrin is an extrinsic protein found towards the cytoplasm. It is a part of cytoskeleton because it provide shape to RBCs".