2. Increase cholesterol in the phospholipid bilayer
1. The plasma membrane of cells is made up of two layers of phospholipids, this is to insure that there is a distinct separation in the contents of the inside of the cell, from the outside. Water (a polar molecule) cannot easily pass through the membrane, hence a non-polar molecule would pass through easier.
2. Cholesterol in the plasma membrane increases fluidity, hence if the plasma membrane's permeability is decreasing due to the cold temperature, increasing fluidity and permeability would then allow the membrane to retain its function.