5.3

• Lipids- water avoiding compounds as found in oil.
• Hydrophobic- basically means "water fearing"
• Fat- made of three-carbon backbone called glycerol attached to three fatty acids which contain long hydrocarbon chains.
• Saturated Fat- fat in which all three fatty acid chains contain the maximum possible number of hydrogen atom.
• Unsaturated Fat- fat that contains less than the maximum number of hydrogen atoms in one or more of its fatty acid chains because some of its carbon atom are double-bonded to each other.
• Steroid- a lipid molecule in which the carbon skeleton forms four fused rings.
• Cholesterol- an essential molecule found in the membranes that surround your cells.
• Diets that consists of large amounts of saturated fats are unhealthy. These kind of diets have bad effects like the increasing amount of lipid-containing deposits in the blood vessels called plaques. This can slow down blood flow and cause heart disease.
  
• Steroids are classified as lipids because they are hydrophobic.
• Too much cholesterol can lead to heart and blood vessel disease.
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Concept Check 5.3

1) What property do lipids share?
They are all hydrophobic and stay away from water.
2)What are the parts of a fat molecule?
A fat molecule consist of a glycerol, fatty acids and a hydrocarbon chain.
3) Describe two ways that steroids differ from fats. Steroids travel around the body like chemical signals and steroids are made of four fused rings.
4) What does the term unsaturated fat on a food label mean? Unsaturated fat means that the food has fat that has less than the maximum amount of hydrogen atoms. Usually found in vegetables and fruits.