Describe the structure of a simple lipid. How are saturated and unsaturated fatty acids different?

Describe the structure of a simple lipid. How are saturated and unsaturated fatty acids different? Give an example of a saturated and an unsaturated fat. Explain what would happen to the relative amount of unsaturated lipids in a plasma membrane when E. Coli bacteria grown at 25° Celsius are then grown at 37° Celsius.