5.3 Lipids include fats and steroids

• oil cannot mix with water it is considered a lipid.


• the name for water evading molecules is hydrophobic which means "water fearing".


• an action of lipids is to surround water contents in cells.


• a saturated fat is a fat with three fatty acids containing the maximum number of hydrogen


• a fat is a three-carbon backbone called glycerol attached to three fatty acids


• unsaturated fats contain less than the maximum number of hydrogen atoms possible


• lipid molecules in which the carbon skeleton forms four fused rings is a steroid


• cholesterol is just one of many types of steroids

Concept Check

1. What property do lipids share?

they all do not mix with water

2. What are the parts of a fat molecule?

a part of a fat molecule is a three-carbon backbone

3. Describe two ways that steroids differ from fats.

1. steroids form from four fused rings

2. fats are made of three fatty acids

4. What does the term unsaturated fat on a food label mean?

unsaturated fats contain less than the maximum number of hydrogen atoms possible