Increasing temperature increases membrane permeability

• 1. Standardised cylinders of beetroot are cut
• 2. Tubes of water are placed in water baths at different temperatures for 15 minutes to equilibrate
• 3. Beetroot cylinders added and left for 10 minutes
• 4. The liquid is then decanted into curvets - as permeability increases so does the red pigment that leaks out of the beetroot cells
• 5. Measured in a decrease in light transmission or an increase in light absorbable using a colorimeter with a green filter
• As temperature increases, the phospholipids have more energy and mice around more and are less tightly packed and the permeability increases too
• Above 45 degrees C the phospholipid bilayer starts to break down so permeability increases and water inside the cell expands and no control over entry and exit of substances
• Cholesterol molecules sit between the hydrophobic fatty acid tails in the membrane , at high temps they are tighter packed and less fluidity stabilising the mpt

  low temp they prevent too tight packing so increases fluidity
• Cholesterol acts as a temperature buffer