UNIT 1: Biochemistry 1.3: The Carbon Chemistry of Life pg. 25 – 28 Carbon Chains – The Backbone of Biochemistry Hydrocarbons - are molecules that are made up of a carbon and hydrogen atoms, such as: methane. Organic molecules - are molecules consisting of a carbon chain, with hydrogen and other atoms (nitrogen, oxygen, and sulfur) attached. Carbon has the ability to form the back-bone of large diverse molecules, because of the carbon’s ability to form bonds (four covalent bonds). These carbon chains (carbon skeletons) can form linear, ringed, and multi – branched molecules. Carbon has the ability to form four single covalent bonds, but may also form double and triple covalent bonds. Carbon molecules can form polymers, complex molecules made up of many repeating monomers, such as; carbohydrates, proteins, and nucleic acids. The lipid molecule is a not a polymer, made up many repeating monomers, but is composed of subunits glycerol and fatty acid chains. Functional Groups Functional group - is a group of atoms that affects the function of a molecule by participating in chemical reactions. Functional groups are usually strongly polar or ionic. They form small reactive groups which allow organic molecules to undergo synthesis and degradation reactions. Characteristics of Functional Groups Large biological macromolecules are influenced by the polar and ionic characteristics of its functional groups, both physically and chemically. These functional groups allow chemical reactions to occur, break and form new bonds. Hydroxyl Carbonyl (OH) (=O) end (=O) mid Carboxyl (COOH) Amino (NH2) Phosphate (PO4) Sulfhydryl (SH) alcohol ethyl Alcohol aldehyde acetaldehyde ketone acetone organic acids acetic acid amino acids alanine nucleic acids glyceraldehydes-3-phosphate cellular molecules mercaptoethanol Dehydration and Hydrolysis Reactions In these reactions H+ and OH- ions are gained or lost from organic molecules. Dehydration reaction requires the removal of water, usually during the building of a larger molecule from smaller subunits. (Anabolic reaction) (Bonding of two glucose molecules to form maltose) Hydrolysis reaction requires the addition of water, usually during the breaking down of larger molecules into smaller subunits. (Catabolic reaction) (Maltose is broken down into two molecules of glucose) Hydrolysis and dehydration reactions are among the most important reactions in cells.