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Experimental Evidence in Support of Fluid Mosaic Model of Plasma Membrane Cell

Introduction of Fluid Mosaic Model Evidence

Experimental evidence of the fluid mosaic model supports the plasma membrane's mosaic arrangement, supports fluid property, maintains the role of lipids molecules, movement of lipid, increasing membrane fluidity of unsaturated fats, and maintain the cholesterol of fluidity membrane.

Some evidence to support the fluid mosaic model is:

A. Mosaic arrangement support of proteins evidence. 

Freeze-fracture electron microscopy of the plasma membrane through Branton (1968) revealed the presence of bumps and depression which are randomly distributed of the mosaic arrangement of proteins. There were later shown to be transmembrane integral proteins particles of the fluid mosaic model.

B. Evidence of Cell membrane's fluid property.

Mobility of plasma membrane proteins due to the fluid property of lipid bilayer was demonstrated through a classical experiment according to D.Frye and M.Edidin (1970). They fused two different types of cultured cells having different surface antigens of proteins. The cell fusion is achieved like that an inactivated parainfluenza virus that is known as Sendai virus of fluid. 

Fluid mosaic membrane

Sendai virus facilities fusion of the biological cell of plasma membranes as well as cytoplasm of both cells to produce a hybrid cell and heterokaryon which are two types of nuclei. when if the two cells are originally labeled with fluorescent antibodies of different colors, fluorescein and rhodamine cells, it is possible at the onset of the fusion to recognize the plasma membrane and each cell. However, the intermixing occurs as the antigens are dispersed and the 2 colors become less detectable of plasma membrane cells. After 40 minutes at 37 degrees Celcius of the intermixing of 2 colors is complete as well as the two antigens can no longer be distinguished from experimental evidence.

Lipid molecules maintaining the role of  fluidity property in the Plasma Membrane

1. Types of movements of lipid molecules. However, in these membranes where lipids are actively synthesized there is smooth ER and there is a rapid flip-flop of specific lipid molecules across the bilayer and there are present certain membrane-bound enzymes that are called phospholipid translocator to catalyze this activity in a proper way. 

2. Role of unsaturated fats in increasing membrane fluidity. A synthetic bi-layer made from a single type of phospholipid changes which through a lipid part of plasma to a rigid crystalline-like hat solid and gel-like that viscous part at a characteristic freezing point of cells. This change process of state is called a phase transition. And their temperature at which it occurs becomes lower if the hydrocarbon chains are short and have double bonds of the plasma membrane. Thus to maintain the fluidity of the membrane and their cells of the organism which living at low temperatures have high proportions of unsaturated fatty acids in their membranes and then do cells at higher temperatures of fats.

In fact, surely membrane transport processes and enzyme activities are found to cease when the lipid bi-layers viscosity increases beyond a threshold level of fats. In contrast, if lipid bi-layers fluidity is increased and the membrane's receptors for the hormone are withdrawn from the cell surface, and there hampering the hormone action of cells.

3. Role of cholesterol in maintaining the fluidity of the membrane. Eukaryotic plasma membranes are found to present a large amount of cholesterol in the plasma membrane which up to one molecule for every phospholipid molecule in cells. Cholesterol molecules orient in the lipid bilayer in the right way and its hydroxyl groups that are close to a polar head bunch of the phospholipids and it's rigid plate-like steroid rings interact with partly immobilize that region of hydrocarbon chains that are closest to the polar head groups in the biological cell membrane which leaving the rest of the chain flexible of fluidity. 

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