membranes

• role of the membrane

  controls what goes in and out of the cell

  compartmentalisation

  recognition

  signalling
• whats in a recognition site

  glycolipids

  glycoproteins
• describe a membranes structure in relation to water

  hydrophyllic head on outside

  hydrophobic tails on the inside
• what proteins are found in the membrane

  gated

  channel

  carrier
• how does signaling work

  hormone binds to receptor - hormone receptor complex formed - travels through to the nucleus - produces a response

  steriods can diffuse through the membrane but same thing
• what is the role of cholesterol

  reduces fluidity
• what does a channel protein do

  can open or close to perform fascillitated diffusion
• what do carrier proteins do

  bind to specific substances and then will change their shape to physically move substance across

  either active transport or fascillitated diffusion depending on the circumstance
• factors affecting diffusion rate

  distance

  temp

  conc gradient

  if its polar/charges
• what is active transport

  transport across membranes
• what is the chemical that is required to change the shape of proteins

  ATP
• define diffusion

  net movement of particles along/down a conc gradient
• define fascillitated diffusion

  diffusion that requires a protein
• what can diffuse across a membrane

  non-polar molecules

  steroids

  small polar molecules
• what is bulk transport

  AT but for larger molecules
• define endocytosis

  taking in of substances into a cell

  cell membrane folds around and meets at the top
• define exocytosis

  mass release of substances from a cell