triglycerides

• one molecule of glycerol attached to three fatty acids
• fatty acids have long 'tails' of hydrocarbon and are hydrophobic, making lipids insoluble in water
• an ester bond is formed between a glycerol molecule and a fatty acid molecule during a condensation reaction
• fatty acids are saturated or unsaturated
• unsaturated fatty acids have a carbon double bond in their hydrocarbon tail
• there are no carbon double bonds in saturated fatty acids
• long hydrocarbon tails contain lots of chemical energy, which is released when they're broken down
• they're insoluble so they don't affect water potential