lipids Flashcards
how is a triglyceride formed
by a condensation reaction of one molecule of glycerol (alcohol) and 3 molecules of fatty acids
how many condensation reactions are required to form a triglyceride
3 condensation reactions so 3 water molecules are removed
how many bonds are found in each triglyceride molecule
3 ester bonds
how is water molecule removed
in a condensation reaction, H is removed from glycerol and OH is removed from fatty acid
why is 1 triglyceride molecule not a polymer
its not made of the same monomers
where are triglycerides usually found
in food (storage molecules)
what do phospholipids do
form a cell membrane around the cell
give other functions of lipids
-conduct heat slowly (so are good thermal and electric insulators)
-stored around delicate organs like liver and kidney
-similar to waxes however it contains alcohol
compare the proportion of oxygen in lipids and carbohydrates
much less in lipids (C:H2:O)
how are fatty acids an R group and give the 2 types
-because numbers of hydrogens and carbons can differ
-saturated and unsaturated
what is a saturated fatty acid
-when the hydrocarbon chain has only single bonds between carbons, bonded to maximum numbers of hydrogen
-most likely to be solid at room temp because chains are packed together
what is an unsaturated fatty acid
-when the hydrocarbon chain consists of at least one double bond between carbons, not holding maximum numbers of hydrogen possible
-most likely to be liquid at room temp
why are unsaturated fatty acids likely to be liquid at room temp
sometimes the double bond causes a bend/kink that prevents the fatty acids from packing tightly, keeping them liquid.
give the properties and their uses of a triglyceride
-ENERGY STORE = due to large ratio of energy-storing carbon-hydrogen bonds to number of carbons, a lot of energy is stored in molecule
-due to high ratio of hydrogen to oxygen atoms triglycerides act as a METABOLIC WATER SOURCE, so they can release water if they are oxidised, essential for animals in dry areas like camels
-triglycerides don’t affect water potential and osmosis because they are large and HYDROPHOBIC making them insoluble in water
-lipids have a relatively LOW MASS so a lot can be stored without increasing the mass if organism and without preventing restriction of movement
how is a phospholipid formed
by 2 condensation reactions resulting in 2 ester bonds
what is a phospholipid made up of
1 glycerol 2 fatty acids chain and a phosphate group (attached to the glycerol)
give the properties of phospholipids
POLAR-the hydrophilic ‘head’ (phosphate group) can attract water as it is charged , so it’ll repel other fats
NON-POLAR-the fatty acid chain is known as the hydrophobic ‘tail’ and it repels water bc it has no charge but it will mix with other fats
because of the properties of phospholipids, how will they arrange themselves in water
-they will arrange themselves in 2 layers called a bilayer
-hydrophobic fatty acids tails will face each other away from water
-hydrophilic heads are exposed to water
what does a phospholipid bilayer form
a membrane structure which makes up the plasma membrane around cells / cell membrane
