lipids Flashcards
what are the function of lipids (basic)?
energy source/store
protection of organs
waterproofing
thermal/electrical insulation
component in cell membranes
what elements are in lipids?
carbon
hydrogen
oxygen
what are the properties of lipids (water)?
non-polar (insoluble in water) but dissolve in non-polar organic substances
what are triglycerides made of?
glycerol
3 fatty acids
what bond is in a triglyceride?
ester bond (between glycerol and hydrocarbon chain)
what happens during the formation of a triglyceride?
condensation reaction
ester bond is formed
3 waters are made as water molecules are removed
what are saturated fatty acids?
all C atoms are joined by single bonds
all C atoms are linked to the maximum possible number of H atoms
what are the properties of saturated fatty acids?
form straight lines
high melting point
molecules align readily so solid
what are unsaturated fatty acids?
they have C double bonds
what are the properties of unsaturated fatty acids?
form bent chains
low melting point
molecules can’t align readily so don’t solidify
what are fatty acids with more than one double bond called?
mono-unsaturated or polyunsaturated fatty acids
what are waxes?
lipids that melt at about 45 degrees C
what are the function of waxes?
animals - insect exoskeleton
plants - leaf waxy cuticle and waterproofing
what are lipoproteins?
complexes of lipids and proteins which occur in blood as plasma
what are LDLs?
low-density lipoproteins
where are LDLs formed from?
diets high in SATURATED fat
what do LDLs do?
build up in blood vessels as fatty deposits in coronary arteries
restrict blood flow
result in angina or myocardial infraction or make an atheroma
what are HDLs?
high-density lipoproteins
where are HDLs formed from?
diets high in UNSATURATED fat
what do HDLs do?
carry harmful fats away from artery walls to the liver for disposal
what does the LDL:HDL ratio show?
the higher the ratio the higher the risk of cardio vascular and coronary heart disease
what is cholesterol?
membrane component (precursor of other molecules)
what are phospholipids?
similar structure to triglycerides but with a phosphate group instead of a fatty acid
what do phospholipids do?
main component in cell membrane
electrical insulation in neurons
what does a phospholipid contain?
hydrophilic head (negatively charged phosphate group interacts with water)
two hydrophobic tails (non-polar fatty acid that doesn’t interact with water)
what happens when a phospholipid combines with water?
micelle (droplet sphere) forms
or
liposome (double layered phospholipid bilayer) forms
what does a liposome do?
traps a compartment of water in the middle separated from external water by hydrophobic sphere
