1. Chapter 5 Section 3 Lipids Mrs. Kerstetter Biology

2. Lipids Lipids Lipids Lipids are generally not soluble in water. Lipids are generally not soluble in water. Which means they are HYDROPHOBIC Which means they are HYDROPHOBIC Lipids are made mostly from carbon and hydrogen atoms. Lipids are made mostly from carbon and hydrogen atoms.

3. Lipid structure

4. Lipids The common categories of lipids are: The common categories of lipids are: fats fats oils oils waxes waxes steroids steroids

5. Lipids What is the function of lipids? What is the function of lipids?

6. Lipids Lipids can be used to store energy. Lipids can be used to store energy. Some lipids are important parts of biological membranes and waterproof coverings. In other words…BOUNDARIES Some lipids are important parts of biological membranes and waterproof coverings. In other words…BOUNDARIES Some circulate in the body as chemical signals to other cells Some circulate in the body as chemical signals to other cells

7. Lipids Many lipids are formed when a glycerol molecule combines with compounds called fatty acids. Many lipids are formed when a glycerol molecule combines with compounds called fatty acids. If each carbon atom in a lipid’s fatty acid chains is joined to another carbon atom by a single bond, the lipid is said to be SATURATED. If each carbon atom in a lipid’s fatty acid chains is joined to another carbon atom by a single bond, the lipid is said to be SATURATED. The term saturated is used because the fatty acids contain the maximum possible number of hydrogen atoms. The term saturated is used because the fatty acids contain the maximum possible number of hydrogen atoms.

8. Lipids If there is at least one carbon-carbon double bond in a fatty acid, it is UNSATURATED. If there is at least one carbon-carbon double bond in a fatty acid, it is UNSATURATED. Lipids whose fatty acids contain more than one double bond are polyunsaturated. Lipids whose fatty acids contain more than one double bond are polyunsaturated. Lipids that contain unsaturated fatty acids tend to be liquid at room temperature. Lipids that contain unsaturated fatty acids tend to be liquid at room temperature. Saturated fats are SOLIDS at room temperature. Saturated fats are SOLIDS at room temperature.

9. Steroids = a lipid molecule in which the C skeleton forms 4 fused rings -all steroids have a core set of 4 fused rings, but they are different in the kinds and locations of functional groups attached to the rings

10. Steroids Classified as lipids because they are hydrophobic Classified as lipids because they are hydrophobicFunctions: 1. Circulate in body as chemical signals 2. Starting point for other steroids Estrogen and testosterone are sex hormones cause major differences in female and male sexual characteristics

11. Steroids

12. Cholesterol Best known steroid Best known steroid Found in molecules that surround your cells Found in molecules that surround your cells Starting point for making other hormones Starting point for making other hormones Bad Rep…Why? Bad Rep…Why? High levels of LDL and VLDL are linked to increase risk of cardiovascular disease High levels of LDL and VLDL are linked to increase risk of cardiovascular disease