Lipids Flashcards
What are the 2 groups of lipids
Phospholipids
Triglycerides
How are triglycerides formed and what are they made of
1 glycerol and 3 fatty acids
condensation reaction of one molecule of glycerol and three molecules of fatty acids eliminating/releasing a water molecule forming an ester bond
How are phospholipids formed and what are they made of
Condensation reaction between 1 glycerol, 1 phosphate and 2 fatty acids releasing a water molecule and creating an ester bond
Function of triglycerides
Large and non polar so have no effect on cells water potential and good energy store
Compact so good source of energy in a small space
Release water when oxidised so great water source
High ratio of c-h bonds so good energy store
What do phospholipids formed and how
A bilayer
The phosphate head faces outwards because its hydrophilic and polar whereas fatty acids face inwards because hydrophobic and non polar
3 differences between phospholipids and triglycerides
Triglycerides have 3 fatty acids and phospholipids have 2 fatty acids
Phospholipids have both hydrophilic and hydrophobic region but triglycerides have no distinct hydrophilic part
Phospholipids form cell membranes so provide structure and control what enters and leaves but triglycerides only act as an energy store Compact
Why are fats solid at room temperature
Made up of saturated fatty acids which have straight parallel hydrocarbon chains that don’t take up much space so are tightly packed and solid at room temperature
Why are oils liquid at room temperature
Made up of unsaturated fatty acids which have bends in their hydrocarbon chains due to their double cc bond, they take up a lot of space so cannot be packed together so are liquid at room temperature
Saturated
No cc double bonds
Unsaturated
Cc double bonds
Test for lipids: emulsion test
Add ethanol and water to sample and shake
Milky/white/ cloudy emulsion produced
