What are lipids?
Lipids are biological molecules containing carbon, hydrogen and oxygen. Compared with carbohydrates, they contain a lower proportion of oxygen.
Lipids are non-polar and hydrophobic, so they are insoluble in water. They dissolve in organic solvents such as ethanol.
Two important groups of lipid are:
- Triglycerides — the main components of fats and oils.
- Phospholipids — lipids in which one fatty acid is replaced by a phosphate-containing group; they are important components of cell membranes.