lipids Flashcards
Describe the test for lipids
1) dissolve solid samples in ethanol
2) add equal volume of distilled water and shake
3) positive result=
how do triglycerides form?
- condensation reaction
- between 1 glycerol and 3 fatty acids
- forms ester bonds
what can the fatty acid chains on triglycerides also be known as
r group
- because number of carbon and hydrogens can vary
what is the difference between saturated and UNsaturated
saturated= the hydrocarbon chain only has SINGLE bonds between carbons
unsaturated= hydrocarbon cahin consists of at least one double bond between carbons
MUST PUT ‘BETWEEN CARBONS’ TO GET MARK!!!
list 4 ways in which triglyceride structure results in its properties
1) large ratio of energy storing carbon-hydrogen bonds (compared to no of carbon atoms) a lot of energy is stored in molecule
2) high ratio of hydrogen to oxygen atoms, so triglcerides act as metabolic water source (can release water if oxidised) good for animals in deserts e.g. camels
3) large and hydrophobic so insoluable in water, so triglycerides do not affect water potential and osmosis
4) relativly low mass, so alot can be stored without increasing mass + preventing movement
how do phospholipids form?
- glycerol molecule, 2 fatty acid chains, phosphate group (attatched to glycerol)
- condensation reaction bonds fatty acids and glycerol
- forms ester bonds
list the properties of phospholipids
- hydrophillic head can attract water (because it is charged)
- hydrophobic tail repels water (because it is uncharged)
- forms phospholipid bilayer membrane structure (akes up plasma membrane around cells)
do hydrophillic heads point out or in
out
do hydrophobic tails point out or in
in
