Cell membrane structure

• cell membrane surrounds cells and most organelles
• cell membrane allows selected molecules to move within or out of the cell
• cell membrane isolates organelles from the cytoplasm so cellular processes may occur separately
• cell membrane allows cells to change shape
• Phospholipids are a type of lipid made from two fatty acids and a phosphate molecule
• phosphate group is polar and hydrophilic
• fatty acid is unpolar and hydrophobic
• when phospholipids are exposed to water they either form a micelle or a bilayer
• The hydrophilic phosphate group in the bilayer faces outwards to the aqueous environment
• cell membranes have a fluid mosaic structure
• a cell membrane iss fluid because the phospholipids are constantly moving
• glycolipids are a lipid with a polysaccharide chain attached
• glycoproteins are a protein with a polysaccharide chain attached
• sterols are a class of molecules that play a role in signalling
• cholesterol is a type of lipid
• cholesterol regulates the fluidity of the cell membrane in animal cells
• less cholesterol means a higher permeability to molecules
• cholesterol assists in bile production in the liver
• cholesterol fits between phospholipids making the membrane less fluid and more rigid
• cell membrane consists of glycolipids, glycoproteins, cholesterol, phospholipids, proteins and protein chanels
• proteins make up around a half of the cell membrane
• many of the proteins in the cell membrane are transmembrane proteins, they are embedded in the membrane but emerge from either side
• some proteins found in a cell membrane are receptors, they bind to signal molecules
• some proteins in the cell membrane are channels allowing specific structures into or out of the cell
• the cell membrane is a fluid consistency, proteins move freely across the surface
• The multitude of proteins and lipids give the cell membrane a 'mosaic' pattern
• cell membrane is fluid, with an underlying structure anchored to a cytoskeleton
• intrinsic proteins are embedded completely/partly through the lipid bilayer
• extrinsic proteins are loosely bound protesins, located outside the membrane
• Plasma Membranes are membranes consisting of a phospholipid bilayer found around and within all cells. The cell membrane is the plasma membrane that surrounds cells.
• Protein Channel is a protein completely spanning the phospholipid bilayer which form water-filled tubes to allow water-soluble ions to diffuse across the membrane.
• Glycoprotein is a carbohydrate chains attached to a protein (often extrinsic) which are part of the cell surface membrane. They act as recognition sites.