Chapter 5.3 Summary

Lipids include fat and steriods

Characteristics of Lipids
lipid
: one of a class of water-avoiding compounds
hydrophobic
: water-avoiding molecules
- surronds and contain the aqueous contents of cells

Fats
fat
: organic compound consisting of a three-carbon backbone (glycerol) attached to three fatty acids
- cushions organs and provides insulation
saturated fat
: fat in which all three fatty acids chains contain the maximum possible number of hydrogen atoms
- ex. most animal fats
- causes heart diseases if body has to much
unsaturated fat
: fat with less than the maximum number of hydrogens in one or more of its fatty acid chains
- ex. fuits, vegetable, fish

Steriods
steroid
: lipid molecules with four fused carbon rings
- circulate in body as chemmical signal
cholesterol
: steroid molecule present in the plasma membranes of animal cells

Concept Checks

1. What property do lipids share?
   Lipids share the property of being hydrophobic.
2. What are the parts of a fat molecule?
   A fat molecule consists of a glycerol, a three-carbon backbone, attached to three fatty acids.
3. Describe two ways that steroids differ from fats.
   One way steroids differ from fats is that their carbon skeleton forms foused rings while fats are constructed of three fatty acids attached to glycerol. The second is steroids circulate in the body as chemical signals and fats store energy for later use.
4. What does the term unsaturated fat on a food label mean?
   The term unsaturated fat on a food label would mean it contains less than the maximun number ofhydrogen atoms in oneor more of its fatty acid chains. Unsaturated fat is healthier than saturated fat and foods such as fish, vegetables and fruits consists of unsaturated fat.