Today, for most people it is no secret that the membranes are a key element in the regulation of biochemical processes in the cell.Due to biological membranes supported by internal homeostasis within cells.Cell membrane vysokoizberatelno regulates the rate of penetration of various biological compounds in the cell, as well as the way out of enzymes and transporters.Furthermore, this structure is a complex biological complex which provides the perception, transformation and transfer of information from the environment into the cell.
cell membrane is a structure which restricts cells and subcellular organelles (lysosomes, mitochondria, Golgi apparatus, etc.).Each cell is a holistic system of membranes constructed with tubular, bags and tanks.Biological membranes - thin wafers (60-70%) lipoprotein and glycoprotein nature.Note that bacterial and plant cells, unlike animals are unable to change their shape as they are surrounded by a thick cell wall.Cell membrane plant body composed of polysaccharides, bacteria of monosaccharides, amino sugars, lipids and amino acids.
structure of the cell membrane.
main components of cell membranes are lipids (60-70%) - phosphatidylcholine, phosphatidylethanolamine, sphingomyelin and cholesterol.Cholesterol attached biomembranes stiffness, so a membrane with a low concentration of cholesterol more elastic.Membrane proteins are presented lipoprotein and glycoprotein complexes (30-35%).Cell membrane in a small amount also contains carbohydrates as part of glycoproteins, glycolipids and glycosaminoglycans (5-10%).The structure of cell membranes and enter the minor compounds (nucleic acids, antioxidants, inorganic ions, coenzymes, etc.).Plasma membranes are closely related and are integral to intracellular membranes of the endoplasmic reticulum (reticulum).The structure consists of granular reticulum membrane and of the smooth endoplasmic reticulum, which divide the interior of the cell into a plurality of compartments.It is of great importance in the regulation of intracellular transport of substances and the flow of metabolic processes.
function of cell membranes.
Cell membranes provide a barrier function, manifested in the form of selective, regulated metabolism with the environment.Through selective permeability into a cell can enter only substances of a certain size.
Transport function of biological membranes allows the transfer of nutrients into cells and the removal of the final metabolite of it.Cell membrane are involved in maintaining the optimum pH.Those compounds which are not capable of cross bilipidny layer, they penetrate by specific carrier proteins, and by endocytosis.Passive transprorta kinds of substances into the cell include diffusion.The active transport of substances carried out with the participation of the sodium-potassium pump.
matrix function of membranes due to certain interposition and orientation of membrane proteins.Significant role in ensuring the mechanical functions have cell walls and in animals - intercellular substance.Receptor function is carried out thanks to special proteins which are localized on the cell membrane.
enzymatic function of biological membranes is linked to membrane proteins and enzymes.For example, the plasma membranes of epithelial cells (intestinal epithelial cells) contain digestive enzymes.
