Lipids Overview: Triglycerides
Made up from one molecule of glycerol and 3 fatty acids.
- Resipiratory Substrate: a trigylceride molecule yields twice as many molecules of ATP than glucose.
- Thermal Insulation
- Buoyancy: lipids are less dense than wate.
- Waterproofing: oils secreted by some animals onto their skins are triglycerides.
They are non polar molecules which means that there is no charge.
The nature of the hydrocarbon chains can differ:
- The number of carbon atoms can change.
- Hydrocarbon chains can have different numbers of hydrogen atoms: if all the carbon-carbon bonds are single, it is saturated. If not, it is unsaturated.
Lipids Overview: Phospholipids
Phospholipids have one glycerol molecule, 2 fatty acids, and a phosphate group.
There is a hydrophilic and a hydrophobic end, due to the ionic phosphate group. Because of this nature, when placed in water, the phospholipids form a bilayer, whereby the hydrophilic heads face outwards, and the hydrophobic tails inwards.
These bilayers are the basis of plasma membranes.