lipids Flashcards
what is a lipid ?
fats, waxes and oils
what is the most common type of lipid ?
the triglyceride
what are lipids / triglycerides used for ?
- for storage
- high energy store
- production of metabolic water
- insulation
- waterproofing
why can it be used for storage ?
they do not affect water potentials and osmosis as they are large and hydrophobic, making them insoluble in water so they can be stored in a compact way
why can it be used for a high energy store ?
lipids have a high proportion of hydrogen atoms relative to oxygen so respiration of lipids yields more energy
why can it be used for the production of metabolic water ?
because some water is produced as a final result of respiration
as the triglycerides can release water if they are oxidised
what are the 2 types of insulation lipids can be used for ?
mechanical insulation- prevents impact
- thermal insulation
what does it mean when a molecule is saturated ?
there is no double carbon to carbon bond
there are only single bonds between he carbons
what does it mean when a molecule is unsaturated ?
it contains at least one double carbon to carbon bond between the carbons
what is a lipid made out of ?
glycerol and fatty acid
what does a triglyceride contain ?
glycerol
3x fatty acids
3x ester bonds
on what does the properties of lipid depend upon?
the length of the fatty acid tails and the saturation
what are all lipids ?
insoluble in water
what is the test for a lipid ?
emulsion test
- lipid + water + ethanol + shake = cloudy white emulsion
where are phospholipids found in ?
in cell membranes
what do phospholipids contain ?
a phosphate group
glycerol
2 fatty acid tails
How are lipid s made ?
the 2 fatty acids bonds to the glycerol via 2 condensation reactions resulting in 2 ester bonds
at does hydrophilic mean ?
can make interactions with water
how are triglycerides made ?
triglycerides are formed via the condensation between one molecule of glycerol and three molecules of fatty acids
so 3 condensation reactions occur to get 3 fatty acids
what is the R group ?
the R group are fatty acids which can be saturated or unsaturated
what can the hydrophilic head of a phospholipid do ?
it can make interactions with water as it is charged so it repels other fats
what is the fatty acid chain known as ? and why ?
known as the hydrophobic tail as it repels water but will mix with fats
what is it called if the phospholipid has 2 charged regions ?
it means that it is polar
how are the phospholipids positioned in water?
in water they are positioned so that he heads are exposed to water and the tails are not
