Chapter Five Concept 5.3

Lipids include fats and steroids.

Characteristics of Lipids:

Lipids: typical class of water-avoiding compounds

-reason why oil doesn't mix with oil.

Hydrophobic: avoids water molecules. (phobic: afraid)

-lipids act as a boundary that surrounds and contains the aqueous. 

-fats are lipids.

Fats:

Fat: organic compound consisting of a three-carbon back bone attached to three fatty acids. 

-some are solid at room temperature

-fatty tissues cushion your organs and provides body with insulation.

Saturation fat: a fat which all three fatty acid chains contain the maximum possible number of hydrogen atoms. 

-all the carbon atoms in fatty acid chains form single bonds with each other.

    (rest are all hydrogen atoms)

Unsaturated fat: contains less than the maximum numbers of hydrogen atoms in one or more of its fatty acid chains. 

-fats in fruits and vegetables and fish are generally unsaturated.

-diets rich in unsaturated fat is unhealthy.

-plaques; build up of lipid containing deposits. 

-plaques reduce blood flow and contribute to heart  disease.

Steroids:

Steroid: a lipid molecule in which the carbon skeletons forms four fused rings.

-when all steroids have  core sets of four rings; differ in the kinds and locations of functional groups attached to the rings.

-classified as lipids because it is hydrophobic.

-circulate in your body as chemical signals.

-estrogen, a female sex hormone and testosterones and males sex hormones all function by circulating.

-variations cause differences.

Cholesterol: an essential molecule found in the membranes that surround the cells. 

-starting point of were our body produces other steroids

-bad reputation because high levels cholesterol contains substances in blood that are linked to increase in cardiovascular diseases. 

Concept Check 5.3:

1. What property do lipids share?

They are all hydrophobic, and all acts like boundaries from aqueous solutions.

2. What are the parts of a fat molecule?

A fat molecule consists of three carbon backbones called glyceral atteched to long hydrocarbon chains. 

3. Describe two ways that steroids differ from fats.

Fat consists of a three-carbon backbone system whereas steroids form from four fused rings. Another reason is because fats use backbone systems which contain long hydrocarbon chains but steroids circulate in your body constantly. 

4. What does the term unsaturated fat on a food label mean?

Unsaturated fat means that the fat builds up lipid-containing deposits where the plaques can reduce blood flow and contribute to heart diseases.