Cell Membrane

The cell membrane is made up of phospholipid bilayer.

Each molecule in the bilayer consists of 3 fatty acids and one glycerol molecule. Both of these are joined with an ester bond. The heads of the bilayer are hydrophilic, which means it loves the water surrounding. The inside of the layer, which are the fatty acids is hydrophobic, meaning they hate the water.

Why two layers?

There are two layers in a bilayer of the cell membrane. This is due to the hydrophobic and hydrophilic ends and bits. If only one layer made the cell membrane, one side of the layer would have to face the water even if it was hydrophobic. This makes sense that there are two layers joined together to make the cell membrane.

Simple! :)

There are proteins channels through the membrane by Active Transport, Facilitated diffusion, and Osmosis.