5.3 Summary

Lipids, Fats, and Steroids!!!

Lipids are water-avoiding compounds such as oil, they are hydrophobic (afraid of water).
-act as a boundary that surrounds and contains watery contents of your cell.
-circulate body as chemical signals
-fats that store energy in body

Fats contain 3 carbon backbone called glycerol attached to 3 fatty acids which contain long hydrocarbon chains. They cushion organs to provide the organs with insulation.
-Some are solid at room temperature
-Oils are liquids at room temperature

Saturated Fat is a fat in which all three fatty acid chains contain the maximum possible number of hydrogen atoms. (Most animal fats are saturated)
Unsaturated Fat is a fat that has less than the maximum number of hydrogen atoms in one or more of its chains. (The fats in fruits, vegetables and fish)

Steroid: is a lipid molecule in which the carbon skeleton forms 4 fused rings.
-they are hydrophobic
-different from fats in structure and function

Cholesterol is a steroid that is found in membranes surrounding cells
-starting point from which the body produces other steroids.
-high cholesterol levels can cause cardiovascular diseases.


Concept Check 5.3
What properties do lipids share?
Lipids share the property of fearing water, or hydrophobic.
What are parts of a fat molecule?
A fat molecule is made up of a glycerol attached to 3 fatty acids.
Describe 2 ways steroids differ from fats.
Steroids differ from fats in it's structure and function.
What does the word unsaturated fat on a food label mean?
The word unsaturated fat on a food label means that the food contains less than the maximum number of hydrogen atoms in one or more of it's fatty acid chains.