lipids Flashcards
what are lipids?
a group of substances that share a number of basic characteristics
what are the basic characteristics of lipids?
-they contain carbon, hydrogen and oxygen atoms
-they are insoluble in water
-they are soluble in organic solvents such as, alcohol and acetone
what are the two main groups of lipids?
triglycerides and phospholipids
what are triglycerides made up of?
one molecule of glycerol and three fatty acids attached to it
what do fatty acid molecules have?
long tails of hydrocarbons
what are the hydrocarbon tails?
they are hydrophobic (repeal water) which makes lipids insoluble in water
how are triglycerides formed?
by a condensation reaction and are broken up by hydrolysis reaction
how are the three fatty acids and the single glycerol molecules joined?
by ester bonds
what is added to the ester bond to break them apart?
a molecule of water
the R-groups on the fatty acids can either be what?
saturated or unsaturated
what is a saturated fatty acid?
a fatty acid which has no double bonds on the main carbon chain
what is an unsaturated fatty acid?
a fatty acid that has one double bond between carbon atoms on the carbon chain
what is a polyunsaturated fatty acid?
a fatty acid that has more than one double bond between carbons on the carbon chain
how are phospholipids composed?
by one glycerol and two fatty acid molecules with a phosphate group
what does the residence of the phosphate group make?
a polar head which is soluble in water with non-polar tails and are hydrophobic in nature, this type if structure have a tendency to form micelles and bi-layers
