lipids 3.1.3 Flashcards
what 3 elements does lipids contain?
carbon, hydrogen and oxygen.
Are lipids polymers?
No
Are they bigger or smaller than macromolecules?
smaller
what are two types of lipids?
triglycerides and phospholipids
What are triglycerides?
Condensation between glycerol and three fatty acids.
What bond is formed in triglycerides?
ester bonds
what are three important functions of triglycerides?
1) energy store: when oxidised 1g of lipid yields twices as much energy as 1g of carbohydrates.
2) heat insulation: lipids stored under the skin reduce heat loss by conduction.
3) protection: fat is often stores around delicate organs eg kidneys
What is the test for lipids?
Dissolve the sample in ethanol, then pour it into a test tube of water. a cloudy white colour indicates lipid is present
What is the R group is fatty acids?
It is the hydrocarbon chain. The number of carbon atoms can vary and they can either be saturated or unsaturated
what are saturated fatty acids?
All the bonds between carbon are single bonds EG fats
What are unsaturated fatty acids?
When some of the bonds between the carbon atoms are double bonds EG oils
What are phospholipids?
When one of the fatty acids is replaced by a phosphate group.
What does hydrophilic mean?
attracts water
is phosphate hydrophilic or hydrophobic?
hydrophilic
what does hydrophobic mean?
repels water
