Explain how the presence of double bonds affects membrane integrity at low temperatures.

1. Presence of C=C double bonds in fatty acid phospholipid hydrocarbon tails causes kinks, thus preventing close packing of phospholipids. [1] [what do C=C double bonds do to the structure of the cell membrane?]
2. This lowers the temperature at which the membrane becomes less fluid. [1]
3. Hence, membranes with more double bonds / unsaturated hydrocarbon tails are more fluid / tend to maintain membrane integrity at low temperatures / vice versa. [1]