THE STRUCTURE OF CELL (PLASMA MEMBRANE)

All the cell have mainly three things:-

1. Cell membrane or plasma membrane and cell wall
2. Nucleus
3. Cytoplasm

• Cytoplasm is the fluid which is present inside the cell.
• Nucleus is cell organelle which is present inside the cytoplasm containing genetic material.

CELL MEMBRANE

• It separates interior of cell from outer environment.
• Cell membrane is the outer boundary of the cell.
• It is thin selectively permeable membrane.

STRUCTURE OF CELL MEMBRANE

• Cell membrane is made up of :-

1. Phospholipids is about 75 percent.
2. Cholesterol
3. Protein-

                 i.Integral protein 

                ii.Peripheral protein
     4.Polysaccharides

FLUID MOSAIC MODEL

• This model is given by Singer and Nicolson in 1972 which describe the structure of plasma membrane.
• According to this this model ,
• Cell membrane is made up of bilayer of phospholipids.
•  Phospholipids
• Phospholipid have two main parts one is hydrophilic(water lover) head and and another is two hydrophilic(water hater) tails.
• Head is made up of phosphate group and tail is made up of fatty acids.
• Cholestrol
• It helps in entring of the molecules inside the cell or exiting of molecules from the cell.
• Proteins
• There are two types of protein is present in cell membrane one is integral (intrinsic) protein which is embedded in both the layer of phospholipids. Integral protein is helpful in transportation of larger molecules like glucose.
• Another one is peripheral (extrinsic ) protein which is embedded in only one layer of phosholipids.

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