Plasma Membrane Summary

The plasma membrane is an essential to the survival and homeostasis of a cell. Plasma membranes are present in both plant and animal cells. The membrane provides protection for the cell and holds tissues together. It regulates the cell’s interaction with its outside environment and what is able to leave and enter the cell. Most importantly the cell membrane controls the movement of nutrients, wastes, oxygen, and water. Managing these factors are vital for a cell’s survival. The membrane has two ways to allow materials to enter or leave the cell. It uses both active transport and diffusion. Diffusion is when materials are permeable to the membrane and move to an area of lesser concentration. The cell membrane moves larger particles needed for the cell with active transport. Often times active transport is needed to transport materials across the concentration gradient. Through endocytosis the membrane allows materials that are within their own membrane to enter into a cell. The materials enter the cell and the membrane fuses in with the cell membrane. The process of exocytosis is merely the direct opposite and takes materials out of the cell. Both of these processes manage the cell membrane’s size. The membrane is made up primarily of lipids and proteins and a very small percentage of it is made of carbohydrates. The lipids make up the lipid bilayer, which is the primary structure of the cell membrane. The cholesterol in the bilipid layer controls the fluidity of the membrane. The proteins that are entrenched in the bilipid layer carry out many functions of the membrane and the cell. Their function is to be receptors, enzymes, etc. The plasma membrane is a prominent part of the cell that is a critical for a cell’s survival.