lipids Flashcards
what do triglycerides consist of
one molecule of glycerol with three fatty acids attached to it
fatty acids in triglycerides overview
- have long tails made of hydrocarbons
- tails are hydrophobic (repel water molecules)
- make lipids insoluble in water
do all fatty acids have the same basic structure?
same basic structure but the hydrocarbon tail changes
what reaction formed a triglyceride
condensation
how do triglycerides form
- fatty acid joins to a glycerol molecule
- ester bond is formed through a condensation reaction
- process happens twice a more to form a triglyceride
what do triglycerides consist of
one glycerol molecule, three fatty acids
how can you tell if a hydrocarbon tail is saturated
fatty acids don’t have any double bonds between their carbon atoms
- the hydrocarbon is saturated with hydrogen
how can you tell if a hydrocarbon tail is unsaturated
unsaturated fatty acids have at least one double bond between carbon atoms which causes the chain to kink
what are lipids found in the cell membrane
phospholipids
structure of a phospholipid
- phosphate group
- glycerol molecule
- 2 fatty acids
phospholipids attraction to water
- phosphate groupoe is hydrophilic and the fatty acid tail are hydrophobic
hydrophilic meaning
attracts water
hydrophobic meaning
repels water
how Is a triglyceride good for energy storage
- long hydrocarbon tails contain lots of chemical energy
-lots of energy released when they are broken down - lipids contain twice as much energy per gram than carbs
how do triglycerides effect water potential
- insoluble so don’t effect water potential of the cell as water cant move into the cell via osmosis
- triglycerides clump together as insoluble droplets in cells because the hydrophobic fatty acid tails face inwards and are protected by the glycerol head
*circle with heads on outside tails in the middle
what do phospholipids do in the cell membrane
form a double layer of hydrophilic heads facing out on either side of the cell membrane
- the centre of the bilayer is hydrophobic so water soluble substances cant easily pass through it
- membrane acts as a barrier to those substances
*phosopholipid bilayer
emulsion test for lipids
- shake test substance with ethanol for a minute until it dissolves then pour the solution into water
- any lipid will show up as milky emulsion
- the more lipid there is the more noticeable the milky colour will be
