Cell Surface Membrane Flashcards
Module 1
Roles of a cell surface membrane
Partially permeable barrier
Site of chemical reaction
Site of cell communication
What are cell surface membranes made of
Phospholipid bilayer, glycoprotein, glycolipids, proteins, cholesterol
What is a phospholipids structure
Polarised Hydrophilic head and hydrophobic tail
What is amphipatic
When some parts are charged and some arent
What happens to phospholipids in water
They form Liposomes and micelles
What is a phospholipid bilayer
When the polar heads of phospholipids are attracted to water and the hydrophobic tails are repelled
What are the parts of the fluid mosaic model
Glycoproteins, channel proteins, phospholipid bilayer, extrinsic protein
What are integral protiens
Span the whole width of the membrane
Many are carrier molecules or channels
Help transport ions, sugars and amino acids
Some are receptors for hormones and neurotransmitters, or enzymes
What are glycoproteins
proteins with attached carbohydrate chains
What are peripheral proteins
Proteins confined to the inner or outer surface of the membranes
May act as receptors, involved in cell signalling or chemical reactions
Glycoproteins and glycolipid function
Acts as receptor sites - involved in cell signalling
Assist in binding cells together
What is cholesterol
Controls membrane fluidity and permeability
More cholesterol = less fluid and less permeable
Important in keeping membranes stable at normal body temp
What are factors affecting membrane permeability
Solvents, temperature, detergents
How do solvents effect membrane permeability
Solvents dissolve lipids in membrane
Some solvents increase permeability more than others
How does temperature affect membrane permeability
low temp - little KE so phospholipids very close together, ice crystals may form and pierce the membrane
Mid temp - temp increases, KE increases, phospholipids move apart
High temp - bilayer starts to melt, H2O expands and puts pressure on membrane, proteins denature