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
what kind of structure do the phospholipids form in water ?
they form a phospholipid bilayer membrane structure which makes up the plasma membrane around cells
draw the structure of a glycerol molecule ?
notes
draw the structure of a fatty acid
notes
display how ester bonds are created in a triglyceride ?
notes
what is the advantage of lipids having a relatively low mass ?
- a lot can be stored without increasing the mass and preventing movement
