Question

State four important functions of the plasma membrane.

Answer 1

Hint: The plasma membrane is the membrane present in all cells that separate the interior of the cell from the outside world, sometimes called the cell membrane. A cell wall is attached to the plasma membrane on its external surface in bacterial and plant cells.

Complete step by step answer:
The four most important functions of the plasma membrane are:
Physical Barrier: Both cells are surrounded by the plasma membrane and the cytoplasm, which is the substance that makes up the cell, is physically isolated from the extracellular fluid outside the cell. This protects all the cell components from the outside world and allows for the occurrence of distinct events within and outside the cell.
Selective Permeability Selective Permeability: Plasma membranes are selectively permeable (or semi-permeable), meaning they can only be passed through by certain molecules. The membrane can easily move through water, oxygen, and carbon dioxide. Generally, ions (e.g. sodium, potassium) and polar molecules are unable to move through the membrane; instead of freely diffusing, they must go through particular channels or pores in the membrane. This way, the membrane will regulate the rate at which the cell will reach and exit certain molecules.

Exocytosis and Endocytosis: Endocytosis is when a cell ingests contents that are comparatively larger than the single ions or molecules going through the pores. A cell may take in large amounts of molecules or even entire bacteria from the extracellular fluid by endocytosis. Exocytosis is when these compounds are released by the cell. In all these processes, the cell membrane plays a significant role. To allow molecules to enter or leave the cell, the shape of the membrane itself changes. It also forms vacuoles, small membrane bubbles which, in order to transport materials to different places in the cell, can transport several molecules at once.
Signaling Cell: The facilitation of contact and signaling between cells is another essential feature of the membrane. It does so through the membrane's use of different proteins and carbohydrates. The proteins on the cell "mark" the cell so that it can be recognized by other cells. The membrane also has receptors that, when molecules such as hormones bind to those receptors, allow it to perform certain tasks.

Note: Plasma membranes are semipermeable and have receptors that assist in contact with cell cells, while the cell wall is fully permeable and has no receptors. The plasma membrane covers the protoplasm and regulates the molecules entering it.