Living organisms have large molecules (polymers) that are important to life. These polymers are built from building blocks called monomers. The chemical reactions are joined together by a dehydration reaction by removing molecule of water, called dehydration synthesis reaction. Polymers can be broken down by hydration reactions. I. Carbohydrates (Saccharides)-sugars and starches Level of structurea. monosaccharides b. disaccharides c. polysaccharides a.Mononsaccharides-basic building block -can 3,4,5,6, or 7 carbon backbone, trioses, tetroses, pentoses, hexoses, etc. -has the basic formula CnH2nOn n=#C backbone -can be found in either a ring or a chain form- every carbon has a hydroxyl group except for one carbon that has carbonyl group. Monosaccharides can be found as either a ring or a chain structure. b. Disaccharides -two monosaccharides put together by removing a molecule of water -important disaccharides sucrose-table sugar (glucose, fructose) maltose(2 glucose) lactose- found in milk (glucose, galactose) The disaccharide, sucrose, can be broken down to glucose and fructose by a hydrolysis reaction or by the addition of water. This is just the opposite of previous reaction c. Polysaccharides- polymers containing many sugar units, usually glucose. Can be linked together by dehydration. Important polysaccharides -1.Starch - plants store excess sugars as starch. -2. Cellulose-found in plant cell walls. -3. Glycogen-is animal starch. -4. Chitin- polysaccharide made out of glucose. Found in cell walls of fungi and exoskeletons of insects Impt. functions of carbohydrates 1. Energy 2. Storage of energy 3. Structure 4. Packaging and lubrication II. Lipids- class of organic compounds that are not water soluble. Lipids will NOT dissolve in water. Classes of Lipids a. triglycerides-(fats and oils) b. steroid c. waxes a. Triglycerides- are composed of 3 fatty acids and glycerolFatty acids have a carboxyl group and a hydrocarbon tail. Palmic acid is a saturated fatty acid with the maximum amount of hydrogens. Linoleic acid is called an unsaturated fatty acid. This means that it contains double bonds and is missing some hydrogen. Synthesis of a triglyceride involves 3 fatty acids and a glycerol. Phospholipids are modified triglycerides. They are made of two fatty acids, glycerol and a charged phosphate group. They are an integral part of all cell membrane. Phospholipids have a hydrophobic and hydrophilic part to their structure. Very seldom in illustrating phospholipids, are all the atoms shown. Instead they are illustrated as such-Cell membrane has two b. Steroids-are lipids. Their basic layers of phospholipids as shown. Cholesterol is an important structure is four interlocking rings. steroid. Cholesterol is a building block for many hormones. Cholesterol is found in many meats and can damage veins and arteries by clogging them. It is also an important component of cell membranes. c. Waxes-are even more water resistant and harder than fats. Insects usually have waxy cuticles and so do the leaves of plants, including fruit skins and petal of flowers. You produce wax in your ears.