Fat

Fat is made of glycerol and fatty acids

fatty acids are linked to glycerol by ester linkage.
3 fatty acid + 1 glycerol = triacylglycerol / triglyceride

Saturated fat: contains only single bonds (molecule is linear). Animal fats (solid at room temperature)
Unsaturated fat: contain 2/3 bonds (molecule is "bent"). Plant and fish fats (liquid at room temperature)

Function of fat is for energy storage

Phospholipid = 2 fatty acid + phosphate group     attached to glycerol
fatty acid is hydrophobic
phosphate group is hydrophillic

Bilayer: when phospholipid is added to water, hydrophobic tails will point towards the interior, the shape is bilayer. It is found in cell membranes.

Steroids: lipids that consist of 4 fused rings.
Cholesterol: steroid found in animal cell membrane
Cardiovascular disease: too much cholesterol in blood