Summary of 5.3

CONCEPT 5.3: Lipids include fats and steroids


Key Terms:


lipid -- oil's inability to mix with water is typical of the class of water avoiding compounds
hydrophobic -- water-avoiding molecules

saturated fat -- fat in which all three fatty acid chains contain the maximum possible number of hydrogen atoms

unsaturated fats -- contain less than the maximum number of hydrogen atoms in one or more of it's fatty acid chains because some of it's carbon atoms are double-bonded to each other

steroid -- a lipid molecule in which the carbon skeleton forms four fused rings

cholesterol -- essential molecule found in the membranes that surround your cells


Notes:

Characteristics of Lipids


* hydrophobic - "water-fearing"

-ex. lipids act as a boundary that surrounds and contains the aqueous (watery) contents of your cells.
* other types of lipid molecules circulate in your body as chemical signals to cells



Fats

* some fats are solid at room temperature and some are liquids at room temperature (oil)
- liquids - saturated fat
- solids - unsaturated fat
* saturated fats may be unhealthy


Concept Check 5.3
1. What property do lipids share?


2. What are the parts of a fat molecule?




3. Describe two ways that steroids differ from fats.
Steroids are classified as lipids because they are hydrophobic, and some steroids circulate in your body as chemical signals.

4.What does the term unsaturated fat on a food label mean?
Contains less than the maximum number of hydrogen atoms in one or more of its fatty acid chains because some of its carbon atoms are double-bonded to each other.