lipids Flashcards
describe the structure of a phospholipid
2 fatty acid tails
glycerol
phosphate head
describe the phosphate in a phospholipid
hydrophilic
- attracts water
describe the fatty acids in a phospholipid
hydrophobic
- repels water
how do phospholipids act as a barrier?
- part of cell surface membrane
- hydrophobic core is created when a phospholipid bilayer forms
- prevents water soluble substances getting through
state 3 functions of phospholipids
- acts as a barrier
- holds proteins in membrane but allows some movement due to weak hydrophobic interactions
- separates external environment from aqueous cytoplasm
how are lipids joined?
ester bonds
what does saturated mean?
no double bonds free
what does unsaturated mean?
double bonds free
if the fatty acid tail is saturated, what does this mean for the membrane?
less fluid
if the fatty acid tail is unsaturated, what does this mean for the membrane?
more fluid
describe the structure of a triglyceride
- 3 fatty acids
- glycerol
- ester bonds
- formed during condensation reactions
- insoluble
what happens when double bonds are present in fatty acids? (unsaturated)
- kinks occur
- causes chain to bend
- cannot pack closely and become liquid
state 4 roles of triglycerides
- energy source
- insulation
- buoyancy
- protection
how do triglycerides provide energy?
3 fatty acids which are dense with energy are broken down via beta oxidation and the energy is released
how do triglycerides provide insulation?
traps air under skin and around vital organs, reducing heat loss
