(c)+Proteins+etc

PROTEINS Yanik The plasma membrane (cell membrane) is made of two layers of phospholipids. The membrane has many proteins embedded in it. The plasma membrane regulates what enters and leaves the cell. Many molecules cross the cell membrane by diffusion and osmosis.

Video about plasma membrane function: media type="youtube" key="JShwXBWGMyY" height="315" width="560" align="center" =Difference between Integral and Peripheral Membrane Proteins= Peripheral membrane proteins are proteins that adhere only temporarily to the membrane with which they are associated. These molecules attach to integral membrane proteins or penetrate the peripheral regions of the lipid layer.

= Another, easier definition is: = There are two types of proteins in the cell membrane: peripheral proteins and integral proteins. As you can guess from the name, integral membrane proteins are permanently connected to the cell membrane. They have large sections embedded in the hydrophobic (middle) layer of the membrane. Peripheral proteins are not bonded as strongly to the membrane. They may just sit on the surface of the membrane, anchored with a few hydrogen (H) bonds.

=Main Job of the Proteins:= Basically, proteins transport ion s and molecules through the plasma membrane and to the places where they are needed throughout the cell. Integral proteins are the hard workers of the cell membrane. Some integral proteins cross the membrane and act as pathways for ions and molecules. Some of the ion movement may not require work (passive transport), but other processes require a lot of energy and pumping action (active transport). When you look at the whole membrane, there are very few integral proteins when compared to the number of peripheral ones.

The Basic Functions of Proteins: Integral proteins can transport molecules and ions through the membrane, facilitated or active transport are two such transport functions.
 * Transportation.
 * The protein can also act as receptors for different hormones or neural signals.
 * The integral proteins can also be cytoskelleton, which function is to connect different cells to each other