Temperature

• what does increasing temp do?

  increasing membrane permeability
• what happens at temperatures below 0 ?

  • Phospholipids do not have much energy = they cannot move very much
  • Phospholipids packed closely together and membrane is rigid
  • Channel proteins and carrier proteins in the membrane DEFORM= increasing the permeability of the membrane
  • ice crystals may form and pierce the membrane making it highly permeable when it thaws
• what may form at temp 0?

  • ice crystals may form and pierce the membrane making it highly permeable when it thaws
• What is the effect of temperatures between 0 and 45?

  • Phospholipids can move around and are not packed as tightly together = the membrane is partially permeable
  • as temp increases = phospholipids have more energy = phospholipids move more = permeability of membrane increases
• what is the increase of temps above 45?

  • Bilayer starts to melt (break down) and membrane becomes more permeable
  • Water inside the cell expands, putting pressure on the membrane
  • channel proteins + carrier proteins deform so they cannot control what enters or leaves the cell = increases permeability of membrane