| Difference between unsaturated and saturated fatty acids | - Unsaturated fatty acids contain at least one double bond in the hydrocarbon chain
- Saturated fatty acids lack double bonds between carbon atoms
- Saturated FA unable to accept more hydrogen |
| Emulsion test | - Sample is obtained - crushing/grinding
- Mixed with ethanol
- Water is added
- Forms emulsion
- Turns cloudy, milky white if lipids are present |
| Roles of lipids | - Energy
- Insoluble - waterproofing
- Insulation - fats are low conductors of heat
- Protection - often stored |
| What is a triglyceride | - A group of lipids
- They have three fatty acids combined with glycerol
- Contains unsaturated fatty acid tails which are hydrophobic and insoluble |
| Mono-unsaturated meaning | - One double bond between carbon atoms |
| Poly-unsaturated meaning | - More than one double bond between carbon atoms |
| What are phospholipids | - A group of lipids
- Made up of two fatty acids, a phosphate and a molecule of glyercol |
| Structure of a phospholipid | - The fatty acid molecules repel water (hydrophobic) - non polar tail
- The phosphate molecules attract water (hydrophilic) - polar head |
| Fatty acids | - Carboxyl group
- Attached to a long non-polar hydrocarbon chain (hydrophobic) |
| Structure of a triglyceride related to its function | - Lots of C-H bonds (stores energy)
- Non-polar and insoluble (does not affect water potential) |
| Structure of phospholipids related to function | - Polar heads forms a bilayer in water
- Water holds phospholipids in place
- Can form glycolipids |
| Triglycerides have a hydrophobic tail.
Explain how this feature of a lipid is important for its function. | - Hydrophobic tails force them to clump together as insoluble droplets
- So they can be stored, as a source of energy
- Without affecting water potential by osmosis |
