THEME: Lipids: classification, structure and biological role. Carboxylic acids Carboxylic acids is а compound whose characteristic functional group is the carboxyl group -COOH , example: Common formula of carboxylic acid: THEME: Lipids: classification, structure and biological role.

Lipid Intro Lipid video Lipid Video

LIPIDS Lipids are a class of biological molecules defined by low solubility in water and high solubility in non-polar solvents. As molecules that are largely hydrocarbon in nature, lipids represent highly reduced forms of carbon and yield large amounts of energy. Lipids are thus the molecules of choice for metabolic energy storage.

Classification Triglycerides Waxes Steroids Phospholipids

Biological functions Fuel - most concentrated form in which potential energy can be stored. Bad conductor of heat - excellent insulation. Protection- padding to protect the internal organs. Building Blocks- Some compounds derived from lipids Lipoproteins - cell walls

Fats vs. Oils Fats are solid at room temperature Oils are liquid at room temperature Both have the same chemical structure

Fatty acids naturally occurring carboxylic acids unbranched carbon chain and an even number of carbon atoms. saturated and unsaturated Fatty acids.

Saturated fatty acid Fatty acid chains that contain only carbon-carbon single bonds are referred to as saturated

Unsaturated fatty acid Those molecules that contain one or more double bonds are said to be unsaturated. There are mono- and polyunsaturated fatty acids.

Structure of fatty acids

Waxes А wax is а monoester formed from the reaction of а long-chain monohydroxy alcohol with а fatty acid molecule. Biological role: They serve as protective coatings on leaves, stems, and fruit of plants and the skin and fur of animals.

Waxes

Steriods All steroids are derivatives of a common structure made up of 4 fused carbon rings. Each different steroid contains different chemical groups attached to these rings 2 major functions of steroids: as a significant part of the structure of cell membranes hormones.

Steriods The most common steroid is cholesterol. found in the cell membrane aids in maintaining the correct fluidity of the membrane. precursor molecule for the synthesis of other steroids including bile salts (aids in the digestion of fats) steroid hormones (such as testosterone, estrogen, progesterone, and cortisol).

Phospholipids derivatives of triglycerides composed glycerol molecule two fatty acids (a diglyceride) third carbon contains a phosphate group and usually some added polar molecule (such as ethanolamine, serine or choline). phosphate is highly charged (and don't forget the additional polar molecule) thus part of the molecule is hydrophilic!

Homework Answer the real life question at the bottom of page 35 in your textbook

Application Read the article Answer the questions on a separate sheet of paper

Closing Lipids are more than just fats