CELL membrane,its Histroy and compostion(1st Part)

                           Cell Membrane

       -It can be defined as

     "Protective doundry of Animal cell"

                 Histroy of cell membrane 

Many of the scientits contributed towards the discovery and composition of cell membrane.

1. Overten(1902): He said that cell membrane is composed of lipid layer Because of easily passage of lipid substances.Actually his target was only about the idea of lipid,he does not have any concept about the different types of proteins in this cell membrane.
2. Collander and Barlund: He was agree with the concepts of overten.                                                                      But he added that cell membrane is composed of lipid and proteins,both have same role in the compostion of cell membrane.
3. Danielli and Davson(1952) Robertson(1960): They proposed a model that was called UNIT MEMBRANE MODEL.                                                                                                 According to this model                                                                 "Cell membrane is composed of lipid bi-layer which is sandwitched between two layers of proteins"                            
   
                                                                                                                   -  Later on this model was rejected.                                                                                                                                                                                Fluid Mosaic model                              According to this model             

           "Cell membrane is composed of lipid bi-layer and the                 protein molecules are embeded in this bi-layer in Mosaic                     Manners"

                     Compostion of Cell Membrane

Lipids:40%

Proteins:60%

Traces of Carbohydrates ETC

                

  Types of LIPIDS present in Cell Membrane

1.Phospholipids:There are two types of phospholipids present in the membrane 

           Caphilins and Lacitins

Functions: 

-Give strenghth to the Cell Membrane.

-Regulate Funtions of Enzymes.

-Use as a carrier if molecules.

2.Stroids: For example Cholestrol

Functions:

-Also Give strenghth to Cell.

-These steroids makes the cell membrane permeable.

3.Sulphoids and Glycolipids: They have various functions in the cell membrane 

-Their main Function is to the make membrane Permeable