Chemical Bonds • Ionic bond – one atom transfers an electron to another atom • Covalent bond – two atoms share electrons • Hydrogen bond – weak attraction between the hydrogen atom of one molecule and the slightly negative atom of another molecule
Chemical Reactions • Chemical reaction – two or more molecules interact turning one compound into another. Example: Rust occurs when iron (Fe) combines with oxygen (O2) • Reactant – starting materials for the reaction • Products – ending material
Lipids • Saturated– Some carbon atoms in the fatty acid chains are double bonded. Solid at room temperature. Example: butter
Proteins • Catalyst – compounds that speed up chemical reactions • Enzymes – specialized proteins that are catalysts in cellular reactions. Lowers the amount of energy needed for the reaction.