Lipids Flashcards
How are triglycerides formed?
condensation reaction
1 glycerol, 3 fatty acids
fatty acids can be saturated or unsaturated
What is saturated?
no carbon double bonds
straight molecule
What is unsaturated?
1 or more carbon double bond
bend(s) in molecule
this means they are less tightly packed, fewer london forces, so lower MP and BP
Why aren’t lipids polymers?
limited to only 3 ester bonds as 3 glycerol
How do fats form droplets?
fats are hydrophobic - doesn’t form intermolecular forces with water
no polar (OH or NH) groups in triglycerides to form hydrogen bonds with water - so triglycerides are insoluble
What are the intermolecular forces between non-polar molecules?
London forces - very temporary, easy to break, weak attraction, occur randomly all over molecule
How are phospholipids formed?
condensation reactions
1 glycerol, 2 fatty acids (unsaturated or saturated), 1 phosphate containing group
Describe a phospholipid molecule
Hydrophilic heads on outside - form IM forces with water in solution
Hydrophobic fatty acids form london forces with each other - form barrier to polar and charged molecules therefore can’t form IM forces with them
How does phospholipid structure relate to function?
amphiatic (polar head and non polar tails) - form bilayers
How does triglyceride structure relate to function (respiratory rate)
Many C-H groups to oxidise, releasing electrons used in ATP production so high energy production so good respiratory rate
How does triglyceride structure relate to function (waterproofing)
hydrophobic(non polar fatty acids) so waterproofing
How does triglyceride structure relate to function (poor electrical and thermal conductor)
non-polar; cannot become charged to lose electrons
What is the test for lipids
add ethanol to sample and shake
add water
if white emulsion forms (milky), lipid present
