Cholesterol is a steroid (a tetrapyrol) with a little chain attached.
Cholesterol is not a fat. (Chemically it is an alcohol)
See the totaly different structure of a fat molecule below
A fat molecule is made of three fatty acids attached to a glycerol.
Each fatty acid in the drawing of a fat molecule to the right is saturated, which is to say it has all the hydrogen atoms (the "H"s in the drawing) it can bear.
Unsaturated fats have one or more than one fatty acid with missing hydrogens
For more information on fats, oils and fatty acids go to newsletter13ext1