lipids Flashcards
what are lipids made from?
carbon, hydrogen and oxygen
how do lipids differ from carbohydrates?
contain much more hydrogen than carbs
what are triglycerides made from?
1 glycerol + 3 fatty acids
what is the difference between saturated/unsaturated fatty acid?
(animals) saturated = contains only single bonds between carbons
(plants) unsaturated = contains at least one double bond between carbons
what does the condensation reaction form?
ester bonds between carbon of glycerol and carbon of fatty acid, forms 3 water molecules
why are triglycerides good for energy storage?
high ratio of energy storing carbon-hydrogen bonds to carbon atoms
why are triglycerides a metabolic water source?
release water when oxidised due to hydrogen to oxygen ratio being high, essential for animals in the deser
why don’t triglycerides affect water potentials?
large and hydrophobic, due to being non-polar, making them insoluble in water
why aren’t lipids polymers?
arent made of repeating units
what is the structure of a phospholipid?
1 glycerol + 1 phosphate ion + 2 fatty acids
why are phospholipids both hydrophobic and hydrophilic?
hydrophobic = (tail) fatty acids are not charged and repels with water
hydrophilic = (head) phosphate ion attracts with water as it is charged
compare triglycerides and phospholipids
- tri have 3 fatty acids, phos have 2 fatty acids
- tri have 3 ester bonds, phos have 2 ester bonds
- tri have no phosphate group, phos do
- tri are hydrophobic, phos are hydrophobic + hydrophilic
- tri are found in adipose tissue, phos are found in cell membranes
emulsion test
- 2cm3 of sample and 5cm3 of ethanol into test tube
- shake thoroughly to dissolve all lipid in solution
- add 5cm3 of water and gently shake
- white emulsion indicated presence of a lipid
