lipids Flashcards
properties of lipids
-insoluble in water but soluble in organic solvents
-energy reserve for respiration
-can exit as fats, oils and waxes
-provide body insulation
what is glycerol
an alcohol with a hydroxyl group on each carbon
what is a triglyceride
-3 fatty acids attached to a glycerol
structure of fatty acids
hydrocarbon chain with an acid group attached (carboxylic acid)
what is a saturated fatty acid
no C=C so molecule is closer together, dense structure. strong intermolecular forces require a lot of energy
what is an unsaturated fatty acid
at least one C= C bond, creates a kink. this prevents molecule coming close together, weak intermolecular forces
where is a saturated fatty acid found
in animal sources
where are unsaturated fatty acids found
vegetable oils, nuts and seeds
(plants)
what is the process of the condensation reaction between glycerol and fatty acids forming a triglyceride
-water is removed from the hydroxyl groups on the glycerol and fatty acid
-this forms an ester bond on each of the three fatty acids to the glycerol
what bond is in a triglyceride
ester bond
role of lipids in an organism
-provide body insulation
-energy reserve for respiration
-fats, oils and wax
-water proofing
-buoyancy
what is a phospholipid and the properties
-one fatty acids of a triglyceride is substituted by a phosphate group
-fatty acids have an even number of carbons
-one saturated, one unsaturated
what is the phospholipid by layer
separates the cell from the environment and is made of two layers of phospholipids
what does amphipathetic mean
a molecule having both hydrophilic and hydrophobic parts
what is cholesterol
a sterol which is a type of lipid
properties of cholesterol
-made from glycerol or fatty acids but 4 carbon based rings
-small hydrophobic molecule
-made in the liver
function of cholesterol
-made in the liver
-sits in the hydrophobic part of the bilayer and regulates the fluidity of the membrane
function of triglycerides
-can transfer energy
-acts as a metabolic water source
-insoluble so doesn’t affect water potential
-low mass so can be stored in animal without affecting the mass
what are phospholipids made of
-a glycerol
-two fatty acids
-a phosphate group
what are the properties of the ‘head’ of the phospholipid
-hydrophilic
-can attract water as it is charged
-repels other fats
what are the properties of the ‘tail’ of the phospholipid
-hydrophobic
-repels water
-will mix with fats
how does cholesterol change the fluidity of membranes at different temps
-at low temp: increases fluidity
-at high temp: reduces fluidity
what effect does cholesterol binding to phospholipid fatty acid tails have on membrane
-increasing the packing of the membrane
-so reduces the fluidity of membrane
