1. Advanced Biology

2. Atoms – the building blocks of matter Nucleus – the center of the atom; the location of neutrons and protons Protons – positively charged particles (p + ) Neutrons – particles that have no charge (n 0 ) Electrons – negatively charged particles that are located outside the nucleus (e - ) Element – a pure substance that cannot be broken down into other substances by physical or chemical means Isotopes – atoms of the same element that have different numbers of neutrons

3. Compound – a pure substance formed when two or more different elements combine Covalent Bond – the chemical bond that forms when electrons are shared Molecule – a compound in which the atoms are held together by covalent bonds Ion – an atom that has lost or gained one or more electrons Ionic Bond – an electrical attraction between two oppositely charged atoms or groups of atoms called ions Van der Waals Forces – when molecules come close together, the attractive forces between these positive and negative regions pull on the molecules and hold them together

4. Chemical Reaction – the process by which atoms or groups of atoms in substances are reorganized into different substances Reactants – the starting substances in a reaction Products – the substances formed during a reaction Activation Energy – the minimum amount of energy needed for reactants to form products in a chemical reaction Catalyst – a substance that lowers the activation energy needed to start a chemical reaction Enzymes – a protein and biological catalysts that speed up the rate of chemical reactions in biological processes

5. Substrates – the reactants that bind to the enzymes Active Site – the specific location where a substrate binds on an enzyme Polar Molecules – molecules that have an unequal distribution of charges Hydrogen Bond – a weak interaction involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom Mixture – a combination of two or more substances in which each substance retains its individual characteristics and properties Solution – a mixture that has a uniform composition throughout; also called homogeneous

6. Solvent – a substance in which another substance is dissolved in Solute – the substance that is dissolved in the solvent Acids – substances that release hydrogen ions (H + ) when dissolved in water Bases – substances that release hydroxide ions (OH - ) when dissolved in water pH – the measure of concentration of H + in a solution Buffers – mixtures that can react with acids or bases to keep the pH within a particular range Macromolecules – large molecules that are formed by joining smaller organic molecules together

7. Polymers – molecules made from repeating units of identical or nearly identical compounds called monomers that are linked together by a series of covalent bonds Carbohydrates – Compounds composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom Lipids – molecules made mostly of carbon and hydrogen that make up the fats, oils, and waxes Protein – a compound made of small carbon compounds called amino acids Amino Acids – small compounds that are made of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur

8. Nucleic Acids – complex macromolecules that store and transmit genetic information Nucleotides – smaller repeating subunits composed of carbon, nitrogen, oxygen, phosphorus, and hydrogen atoms that make up nucleic acids