1.5 Lipids Flashcards
How do you test for lipids?
emulsion test
describe how to perform a emulsion test, and what results show a positive outcome
mix ground sample to be tested with ethanol.
Add distilled water.
positive result for lipids indicated by a cloudy white emulsion.
What are the roles of lipids?
source of energy
waterproofing
insulation
protection
What are lipids soluble and insoluble in?
soluble organic solvents
eg. alcohols and acetone
insoluble in water
What is a triglyceride?
an individual lipid molecule made of a glycerol molecule and three fatty acids
What bond is there between fatty acids and glycerol?
ester bond
When is a fatty acid described as saturated?
no C=C double bonds
what does mono unsaturated mean?
one double bond in the carbon chain
What does poly-unsaturated mean?
more than one double bond in the carbon chain
What are phospholipids?
a lipid with a phosphate head and two fatty acid tails attached to a glycerol body
it has a hydrophobic tail and a hydrophilic head
What is the hydrophobic head on a phospholipid?
phosphate group
What is the hydrophilic tail on a phospholipid?
fatty acid tail
are phospholipids polar or non-polar?
polar
What is the test for lipids?
emulsion test
white cloudy emulsion if present
How do you do an emulsion test for a lipid?
add ethanol to sample in test tube
shake tube thoroughly to dissolve lipid in sample
add water and shake gently
cloudy white emulsion means lipid is present
