Chapter 5 Section 3 Lipids Mrs Kerstetter Biology

Chapter 5 Section 3 Lipids Mrs. Kerstetter Biology

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

Lipid structure

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

Lipids n What is the function of lipids?

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

Lipids Many lipids are formed when a glycerol molecule combines with compounds called fatty acids. n 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. n n The term saturated is used because the fatty acids contain the maximum possible number of hydrogen atoms.

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

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

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

Steroids

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