The Fluid Mosaic model

[Snorlax]

Just wondering what the definition is in other textbooks.
Not very clear in the Nelson Biology as it only states its 'mosaic' due to the specialised protein molecules embedded in the bylayer.
It also doesn't state anything about the 'fluid' part, but i did some research and just says due to its frequent lateral movement of the phospholipids.
Any clearer definitions would be nice (what it may say in NoB etc..)

[kenhung123]

Fluid because the embedded components can freely move laterally and phospholipids across the membrane are able to reciprocate

[Yacoubb]

I think kenhung mentioned this in his comment but in my opinion, the fluid mosaic model can be looked at in three aspects:

1) protein channel
2) arrangement of phospholipids in the phospholipid bi-layer.
3) movement and flexibility of the plasma membrane.

The plasma membrane is made up primarily of phospholipids, forming the phospholipid bi-layer, and protein molecules forming the protein channel. Hence - its mosaic (sort of like pattern) When the plasma membrane moves, it moves in a lateral movement; that is, if the upper layer moves, the bottom layer also moves. This laterall movement is actually partially controlled by the presence of cholestrol in the plasma membrane, which reduces fluidity in moderate temperatures to retain the lateral movement of the membrane, or increase membrane fluidity in cold climates. Hence, its ability to move - fluid.

The semi-permeable membrane itself is actually also an asset that justifies its fluid-mosaic model; its ability to allow the movement of substances due to it being partially permeable.

Someone please fix up anything that is inaccurate, but I'm pretty sure the reasons about justify its description as a fluid-mosaic model.

[Stick]

Correct me if I'm wrong but I was told that we don't really need to explain the 'fluid' and 'mosaic' terms directly - we just describe the plasma membrane model as a whole.

[Yacoubb]

Correct me if I'm wrong but I was told that we don't really need to explain the 'fluid' and 'mosaic' terms directly - we just describe the plasma membrane model as a whole.

Yeah Stick you don't need to know the definition of it, or anything about it really. The main things you should know are:

- components of the plasma membrane.
- role of each component in the plasma membrane.
- five forms of transport across the membrane:
* Osmosis
* Diffusion
* Facilitated Diffusion
* Active Transport
* Vesicular transport -> endocytosis and exocytosis