Plasma membrane is also known as cell membrane and it is the outermost layer of the animal cells. Plasma membrane is the selectively permeable lipid bilayer found in the cells. Unlike cell wall, cell membrane is present both in the animal cells as well as plant cells. Plasma membrane is composed of proteins and lipids and there are various processes in which the biological molecules participate.
Plasma membrane or cell membrane is the outer most boundary of the cell. However, in most plants cells, it is covered by a cell wall. Cell membrane is chemically composed lipids and protein; 60-80% is proteins, while 20-40% is lipids. In addition there is a small quantity of carbohydrates.
Many biologists contributed to establish the structural organization of cell membrane. It was proposed an earlier that cell membrane is composed of lipid belayed sandwiched between inner and outer layers of protein. This basic structure is called the unit membrane and is present in all the circular or organelles. The modern technology has revealed that lipid by layers are not sandwiched between two protein layers.
The protein layers are not continues and are not confined to the surface of the membrane but are embedded is lipid layers in a mosaic manner. This discovery led to the purposely of fluid mosaic model. This model at present is the most accepted one. Cell membrane also contains charged pores through which movement of materials takes place, both by active and passive transport.
In many animals' cells, the cell membrane helps to take in materials by enfolding in the form of vacuoles. This type of intake is termed as which can be either neurons the cell membrane transmits never impulses from one part of the body to the other to keep coordination.
The plasma membrane is a phospholipid bilayer eith embeded proteins, it has the important function of regulating the entrance and exit of substances in and out of the cytoplasm .
