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Hello students welcome you all hope you are doing great in your respected classes. Let take some flashback of the previous topic lastly we discussed about what is cell and what are the physical appearance of the cell now today's lecture will be the second part of the cell lipid barrier of the cell membrane
Q. What is the lipid barrier of the cell membrane and how it prevents from the water substances penetration?
Now let me explain you simply or in simple terms basically the cell membrane contains lipid bilayer which is made up of very thin lipids only two the molecules are thick besides these molecules large globular proteins also found.
- Lipid bilayer composition
A. Phospholipid molecules
In this phospholipid molecule there are two ends of the molecule one end is hydrophilic and the other end is hydrophobic, hydrophilic is also known as water loving that means this end is soluble in water and non soluble in fats while as the other end is hydrophobic which is fat loving and soluble in fats and non soluble in water.
On the other hand the hydrophobic end has the tendency to congregate at the middle of the said membrane and are fluid in nature the fat molecules can easily flow from one end to another end. For example alcohol, CO2 and oxygen etc.
While as the the hydrophillic portion has the ability to cover the whole surface with water and acts as a blanket.
B. Lipid bilayer special character
- Fluid like substance.
- Molecules can flow from one end to another end in that fluid for example proteins.
- Cholestrol driver eg steroid nucleus which is highly volatile with the hydrophobic sites of the membrane and are easily penetrated by that area.
C. Cell membrane proteins
Basically proteins are the body building blocks they made the body mass. The proteins are floating upon the lipid bilayer for example football is floating upon the water body.
Cell membrane proteins contains **glycoproteins which are of two types integral proteins which are transported through the membrane while as the other one is peripheral proteins which are linked to the one surface of the membrane and are not been transported.