The fluid mosaic model

Fluid mosaic refers to model of cell membrane structure. The lipid molecules give fluidity and proteins in the membrane give it a mosaic (patchwork) appearance. The molecules can move about.

Main features of the fluid mosiac model:

• Bilayer of PHOSPHOLIPID molecules froming basic structure.
• Various protein molecules floating in the phospholipid bilayer, some completely fress, some bount to other components or to stuctures within the cell.
• Some (extrinsic) proteins partially embedded in the bilayer on the inside or the ouside face; other (intrinsic) proteins completely spanning the bilayer. 

Glycoproteins and Glycolipids

Some of the phospholipid molecules making up the bilayer, and some of the proteins found in the membrane, have small carbohydrate parts attached to them. Where phospholipids have carb part attached they are called glycolipids. Where protein molecueles have carb attached they are called glycoproteins.

Membrane components and their roles

Membrane stability and fluidity- Cholesterol. Gives some eukaryotic cells mechanical stablility. This steroid molecule fits between fatty acid tails and helps to make the barrier more complete, so substances like water and ions cannot pass easily and directly through the membrane. Makes it more impermeable. 

Membrane transport and functions

Channel proteins- allow movement of some substances across the memb. Some molecules and ions are too large and too hydrophilic to pass directly through the…