Biology Chapter 5: Lipids

- the one class of biological molecules that does not include/form true polymers- generally not big enough to be considered macromolecules- grouped together because they share one important trait: they mix poorly, if at all, with water- thus are hydrophobic

Their molecular structure

- consist mostly of hydrocarbon regions- varied in form and function- include waxes and certain pigments- also fats, phospholipids and steroids

- not smaller molecules, large molecules assembled from smaller molecules by dehydration reactions- constructed from two kinds of smaller molecules: glycerol and fatty acids

A 3 carbon alcohol with a hydroxyl group attached to each carbon

- a fatty acid has a carboxy attached to a carbon skeleton- contain a long carbon skeleton, usually 16 to 18 carbon atoms in length

A carboxyl group which is the functional group that gives the molecules the name fatty acid

Hydrocarbon chain

- the relatively non polar C--H bonds in the hydrocarbon chains of fatty acids- fats separate from water because the water molecules hydrogen bond to one another and exclude fats

- three- a bond b/w a hydroxyl group and a carboxyl group

- resulting fat of a bond b/w a hydroxyl group and a carboxyl group- consist of 3 fatty acids linked to one glycerol molecule

- they can be the same - or they can be two or three different kinds

Terms refer to the structure of the hydrocarbon chains in the fatty acids

- if there are no double bonds between carbon atoms composing in a chain, then as many hydrogen atoms as possible are bonded to the carbon skeleton- and is said to be saturated with hydrogen

- has one or more double bonds- with one fewer hydrogen atom on each double-bonded carbon- nearly all double bonds in naturally occurring fatty acids are cis double bonds, which cause a kink in the hydrocarbon chain wherever they occur