The Structure Of Plasma Membrane :


plasma membrane are composed by two main parts , phospholipids and proteins.In the year of 1972 S.Singer and G.Nicolson introduced the fluid-mosaic model of the Plasma Membrane structure.
Each of the phospholipid molecule has a polar head (hydrophilic head) and a pair of non-polar tails(hydrophobic tail) . Plasma membrane arrange themselves in two layers (bilayer) .Phospholipid contain cholesterol to links the fatty acid together (for  the stabilise , strenghten and flexible) .

THE PLASMA MEMBRANE IS selectively permeable . Also known as Semi-permeable.


The movement of substances across the plasma membrane:passive transport .


passive transport means:  The movement of some substances across the plasma membrane without any input of any energy .


Simple Diffusion :
Simple diffusion is the net movement of molecules or ions from a region of higher concentration to a region of a lower concentration (going down a concentration gradient) until equilibrium is achieved .


example of substance : Oxygen , Carbon dioxide and lipid-soluble molecules .


Osmosis : The Diffusion Of Water .
This process only involves in Water molecule. Moves from a region of low solute concentration to high solute concentration . [High water concentration refers to a solution that has a low concentration of solute in the water . It means , it has high water concentration , so the solute concentration is low] .The net direction of osmosis depends on the relative concentration of solutes inside and outside the cell .


Facilitated Diffuision .






This process does not required ATP [adenosine triphosphate] . But , it required a cell membrane proteins called Carrier Proteins to carry  the molecule across the plasma membrane from a region of  Higher concentration to a region of a  lower concentration .
Pore Proteins is a form of pores or channel (liang) . Have specific interior charateristics that only allow specific ions to pass through .

The movement of substances across the Plasma Membrane: Active Transport .










Active transport means :The net movement of molecules of ion against concentration gradient from lower concentration to higher concentration . Another terms for active transport is active transport pump . Active transport does requires ATP [Adenosine Triphosphate]






Officially Done By : SYASYA NUR IFFAH .
Refrence : Biology Text Book Form 4 .
p/s : saya still student . if ade salah about the fact yg sy post . sila lah beritahu untuk saya betulkan . tq :)






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