Biochemistry of lipids Flashcards
what do lipids exclusively contain?
carbon hydrogen and oxygen
the structure of triglycerides are based around
one molecule of glycerol
joined to each glycerol molecule are…
three fatty acid chains, these are long hydrocarbons with a carboxyl group on one end
where do the fatty acids join on the glycerol molecule
where the OH groups are
the reaction that joins fatty acids and OH groups is a
condensation reaction, because three fatty acids join to 3 different OH groups three condensation reactions are effectively taking place. this produces 3 molecules of water
fatty acids are said to be saturated if
there are NO C=C DOUBLE BONDS in the hydrocarbon chain
features of saturated fatty acids
form straight chains and have high melting points
fatty acids are said to be unsaturated if
there ARE C=C double bonds in the hydrocarbon chains
features of unsaturated fatty acids
form bent chains and have low melting points
if fatty acids have MORE THAN ONE C=C DOUBLE BOND they are said to be
polyunsaturated
the structure of phospholipids is similar to that of …. and why
triglycerides as they are still based around one molecule of glycerol. they also have two fatty acid chains and a phosphate group
phospholipids are said to be …….
polar molecules
(phospholipids) the phosphate head is
hydrophilic (water loving)
(phospholipids) fatty acid tails are
hydrophobic
when phospholipids mix with water they can form
droplets or a phospholipid bilayer
why can phospholipids form droplets
they form droplets when the phosphate heads are in contact with the water and the fatty acid tails are excluded from it
phospholipid bilayer
this captures a pocket of water within the double layer. this structure is found in cell membranes
how do you test for lipids
using the emulsion test. add a sample to a grease free test tube. then add ethanol to the sample and mix by inverting several times. add water to the test tube. if a cloudy white emulsion or precipitate is formed then a lipid is present.
