Lipids Flashcards
What are lipids
Lipids are large complex molecules known s macromolecules which means they aren’t built from repeating units.
They are fats and oils
What molecules does lipids contain
Carbons, hydrogen and oxygen
Why are lipids non polar
Their electrons are evenly disrupted. This is why lipids don’t dissolve in water (non soluble)
How is a triglyceride made?
One glycerol molecule bonded to 3 fatty acids which are synthesised by an ester bond through the process of esterfiction. They form 3 ester bonds by 3 condensation reactions leaving behind 3 water molecules
What are the uses of a triglyceride?
They have long hydrocarbon chains which allows for storage of energy.
They can also be broken down to release a lot of energy
What is a fatty acid?
It is a carboxylic acid consisting of a hydrocarbon chain ( its tail) and a terminal carboxyl group
What is the difference between a saturated and unsaturated fatty acid?
A saturated fatty acid have no double bonds present between the carbon atoms whereas an unsaturated fatty acid has double bonds between the carbon atoms which causes the molecule to kink which stops them from packing close together making them liquid at room temperature (oil)
What makes up a phospholipid ?
A phosphate group , a glycerol and 2 fatty acids
Describe the structure of a phospholipid
They have a hydrophilic head but a hydrophobic tail so their tails stick out of water which is known as surfactants
Where does the body manufacture cholesterol?
Liver and intestine
What is the importance of cholesterol?
They are positioned between phospholipids which adds stability to cell membranes . They also regulate the cells fluidity by keeping the membranes fluid at low temperatures and stopping them from becoming too fluid at high temperatures
Identification of lipids
The emulsion test
Mix sample with ethanol and then add water . If white emulsion if formed at the top a lipid is present
If clear it is negative
