CELL MEMBRAN (STRUCTURE OF THE CELL MEMBRAN)

BY MUHAMMAD ASWAN

Definition of The Cell Membran

Cell Membran is the layer to separate that a cell with the other cell as well to separate into cell the organell

The General of Component Cell Membrane

Components of The Cell Membran a. The major constituens of tha

cell membran are lipid and protein

b. Membran Protein and Lipid are arranged in particullary fashion, both contribution to containt the cell and to selectively allowing or blocking the traffic of certain substance of through the cell

c. Such arrangement of molecules provides fluidty to cell membrane

Components of The cell Membran : Lipid

a. Phospholipid are amphiphatic molecules (with hydrophobic tail and hydrophilic head)

b. One of phospholipid tails exits mostly in a trans configuration providing more fluidity to the membrane

c. Cholesterol is a rigid molecule that makes membrane less fluid.

How Are Phospholipid Organized in the Cell Membran ?

a. Phospholipid constitute two mirror – image oriented layer – the lipid bilayer

b. The hyrdrophilid heads are exposed to the high content water region, while the hydrophobic tails constitute a barrier imprenetable to almost all substance

Components of the Cell Membrane : Membrane Protein

a. Membrane Protein are embedded in the fluid matrix of lipid bilayer.

b. More than 50 types protein have been found in the plasma. Membrane protein determine most of the membrane specific function.

c. Transport membrane, enzymes and receptor protein (membrane protein that interact with the other cell or molecules) include the vast majority of membrane protein.

Fluid Mosaic Model a. Fluid – because

individual phospholipid and proteins can move side –to – side within the layer, like it’s a liquid

b. Mosaic- because of the pattern produced by the scattered protein molecules when the membrane is viewed from above.

Semipermeable Membrane

Small molecules and larger hydrophobic molecules move through easily. e.g. O2, CO2,

H2O

Semipermeable Membrane

Ions, hydrophilic molecules larger than water, and large molecules such as proteins do not move

through the membrane on their own.

Function of Cell Membranea. Provide a binding site for enzymesb. Interlocking surfaces bind cell

together (junction)c. Contain the cytoplasm (fluid in cell)d. Protective barriere. Regulate transport in & out of cell

(selectively permeable)f. Allow cell recognitiong. Provide anchoring site for filament

of Cytoskeleyon

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