Flashcards in Structure and function of membranes Deck (10):
What are the functions of membranes at cell surface?
-Act as a barrier and control what enters and leaves the cell.
-Allow cell communication.
-Allow cell recognition.
What are the functions of membranes within cells?
-Control what leaves and enters organelles within a cell.
-Site of chemical reactions.
What is the fluid mosaic model?
-Suggests the arrangement of molecules in a membrane.
-Have a phospholipid bilayer made from phosphate hydrophilic heads and fatty acid hydrophobic tails.
-It is "fluid" due to the phospholipids constantly moving.
-Contain cholesterol molecules within the bilayer.
-Channel and carrier proteins within the bilayer.
-Have glycoproteins and glycolipids.
What are the functions of the phospholipid bilayer?
-Head is hydrophilic so attracts water, and tail is hydrophobic which repels water.
-Arranged in a way where heads face outwards and tails face inward and produce a hydrophobic core.
-The core doesn't allow water-soluble substances (like ions) through.
What are the functions of cholesterol?
-A type of lipid which fits between phospholipids causing them to pack closer together.
-Regulates the fluidity of the membrane.
What are the functions of channel proteins?
-Produce a hydrophilic channel where small and charged particles can pass through.
What are the functions of carrier proteins?
-Involved in transport of molecules and ions across the membrane by active transport or facilitated diffusion.
What are the functions of glycoproteins and glycolipids?
-Glycoproteins=proteins with a polysaccharide chain attached to it.
-Glycolipids=lipids with a polysaccharide chain attached to it.
-They stabilise the membrane by forming hydrogen bonds with surrounding water molecules.
-Sites where hormones, antibodies etc bind to.
-Act as receptors for cell signalling.
-act as antigens.
What is cell signalling?
-How cells communicate with each other.