| A | B |
|---|
| Atom | The basic unit of matter. |
| Nucleus | The center of the atom which contains the protons and the neutrons. |
| electron | Negatively charged particle; located outside the atomic nucleus. |
| element | Substance consisting entirely of one type of atom. |
| isotope | Atom of an element that has a number of neutrons different from that of other atoms of the same element |
| compound | Substance formed by the chemical combination of two or more elements in definite proportions |
| ionic bond | Bond formed when one or more electrons are transferred from one atom to another. |
| ion | Atom that has a positive or negative charge. |
| covalent bond | Bond formed by the sharing of electrons between atoms. |
| molecule (end sec1) | Smallest units of most compounds. |
| cohesion | Attraction between molecules of the same substance. |
| adhesion | Attraction between molecules of different substances. |
| mixture | Material composed of two or more elements or compounds that are physically mixed together but not chemically combined. |
| solution | Mixture of two or more substances in which the molecules of the substances are evenly distributed. |
| solute | Substance that dissolves in a solvent to make a solution. |
| solvent | Substance in which a solute is dissolved to form a solution |
| pH scale | Measurement system used to indicate the concentration of hydrogen ions in solution; ranges from 0 to 14. |
| acid | Compound that forms hydrogen ions in a solution. |
| base | Compound that produces hydroxide ions in a solution. |
| buffer (end sec2) | Weak acid or base that can react with strong acids to help prevent sharp, sudden changes in pH. |
| monomer | Small unit that can join together with othee small units to form polymers. |
| polymer | Large compound formed from combinations of many monomers. |
| carbohydrate | Compound made up of carbon, hydrogen, and oxygen atoms; major source of energy for the human body. |
| monosaccharide | A single sugar molecule. |
| polysaccharide | Large macromolecule formed from monosaccharides. |
| lipid | Macromolecule made mainly from carbon and hydrogen atoms; includes fats, oils, and waxes. |
| nucleic acid | Macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorus. |
| nucleotide | Monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base. |
| ribonucleic acid (RNA) | Single-stranded nucleic acid that contains the sugar ribose. |
| deoxyribonucleic acid (DNA) | Nucleic acid that contains the sugar deoxyribose. |
| protein | Macromolecule that contains carbon, hydrogen, oxygen, and nitrogen; needed by the body for the growth and repair and to make up enzymes. |
| amino acid (end sec3) | Compound with an amino group (NH2) on one end and a carboxyl group (COOH) on the other end. |
| chemical reaction | Process that changes one set of chemicals into another set of chemicals. |
| reactant | Element or compound that enters into a chemical reaction. |
| product | Element or compound produced by a chemical reaction. |
| activation energy | Energy needed to get a reaction started. |
| catalyst | Substance that speeds up the rate of a chemical reaction. |
| enzyme | Protein that acts as a biological catalyst. |
| substrate (end sec4) | Reactant of an enzyme-catalyzed reaction. |
