[Music] what is the basic unit of life yes the cell is the basic unit of life to define the cell can be a limited space entity that does metabolic functions this limitation is due to the presence of a membrane called the plasma membrane let us quickly understand the nature and the structure of the plasma membrane what is the other name for plasma membrane the plasma membrane also called the cell membrane defines the boundary of a cell there is no such cell that exists without the plasma membrane what is the exact role of the plasma membrane it separates the intercellular components of the cells from that of the extracellular space the the plasma membrane defines the boundary also for the organel in eukaryotic cells that are termed membranebound organel the structure of cell membrane is well explained using the fluid mosaic model proposed by singer n Nicholson according to this model the plasma membrane is a lipid bilayer in which proteins are embedded in a random fashion the lipids are usually phospholipids having a head and a tail a on which hydrophilic phosphate heads are oriented outwards and hydrophobic tails are facing inwards the proteins are of two types namely the intrinsic and extrinsic proteins what can we understand by the terms intrinsic proteins and extrinsic proteins intrinsic proteins also called integral proteins are embedded in the lipid layer and act as carriers enzymes transport channels Etc extrinsic proteins are the peripheral proteins Loosely bound to the membrane and act as receptors recognition centers Etc talking about the functions of the cell membrane it provides a proper shape to the cell keeps the adjacent cells in contact and plays an important role in transport interestingly the cell membrane is selectively permeable and semi-permeable in nature this is because the cell membrane allows only the selective materials to pass through it allows the transport of molecules like water minerals ions glucose amino acids oxygen carbon dioxide Etc these are the crisp details of the plasma [Music] membrane