Biology Chapter 5: Lipids

Lipids

23 cards   |   Total Attempts: 182
  

Cards In This Set

Front Back
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
The hydrophobic behavior of lipids is based on what?
Their molecular structure
Other characteristics of lipids include what?
- consist mostly of hydrocarbon regions- varied in form and function- include waxes and certain pigments- also fats, phospholipids and steroids
Fats
- not smaller molecules, large molecules assembled from smaller molecules by dehydration reactions- constructed from two kinds of smaller molecules: glycerol and fatty acids
Glycerol
A 3 carbon alcohol with a hydroxyl group attached to each carbon
Fatty acids
- a fatty acid has a carboxy attached to a carbon skeleton- contain a long carbon skeleton, usually 16 to 18 carbon atoms in length
The carbon at the end of a fatty acid's carbon skeleton is part of what?
A carboxyl group which is the functional group that gives the molecules the name fatty acid
The rest of the carbon skeleton is composed of what?
Hydrocarbon chain
What is the reason why fats are hydrophobic?
- 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
In making fat, how many fatty acid molecules are each joined to glycerol by an ester linkage?
- three- a bond b/w a hydroxyl group and a carboxyl group
Triacylglycerol
- resulting fat of a bond b/w a hydroxyl group and a carboxyl group- consist of 3 fatty acids linked to one glycerol molecule
What are the similarities and differences in the fatty acids in a fat?
- they can be the same - or they can be two or three different kinds
Saturated and unsaturated fats
Terms refer to the structure of the hydrocarbon chains in the fatty acids
Saturated fatty acid
- 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
Unsaturated fatty acid
- 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