1.5: Lipids Flashcards
Triglycerides
One molecule of glycerol and 3 fatty acids attached to it
Fatty acids made of
hydrocarbons
Fatty acids have ‘tails’ which are
hydrophobic
Hydrophobic
repel water molecules
water hating
Lipids are … in water
insoluble
Fatty acids basic structure
1 carbon atom
double bond to oxygen atom
single bond to OH ion
single bond to ‘R’ group
R group is
variable group
How is fatty acids linked to glycerol
carbon atom on fatty acid
Triglycerides formed
condensation reaction
occurs 3 times between each fatty acids w/ the glycerol
Bond in triglyceride formation
ester bond
Two types of fatty acids
saturated and unsaturated
Difference between saturated and unsaturated fatty acods
in the hydrocarbon tails (r groups)
Saturated fatty acids
Contain no double bonds between C atoms
‘saturated’ with hydrogen
Unsaturated fatty acids
Contain at least one carbon-carbon double bond
cause the chain to kink
Lipids found in cell membrane
phospholipids
Structure of a phospholipid
Glycerol
phosphate group
2 fatty acids
Hydrophilic
Attract water molecules
water loving
Whats hydrophilic/phobic in a phospholipid
phosphate group = Hydrophilic
fatty acid tails = Hydrophobic
Triglyceride function
Energy storage molecules
Where is lots of chemical energy stored
hydrocarbon tails of fatty acids
Triglycerides in cells
Clump together as INSOLUBLE DROPLETS
Phospholipids make up
bilayer in cell membrane
Why is it a bilayer not one layer
hydrophilic heads facing out on either side = double layer
Cell membrane acts as a barrier to
why
water-soluble substances
as centre of bilayer is hydrophobic tails
Test for lipids
Emulsion test
Steps in the Emulsion test
shake the test substance with ethanol so it dissolves
add solution to distilled water
presence of lipid = milky emulsion layer
