| A | B |
|---|
| atom | the smallest unit of matter that cannot be broken down by chemical means |
| element | a substance made of only one kind of atom, and therefore a pure substance |
| compound | a substance made of the joined atoms of two or more different elements |
| molecule | a group of atoms held together by covalent bonds |
| ion | an atom or molecule that has gained or lost one or more electrons |
| cohesion | an attraction between substances of the same kind |
| adhesion | an attraction between different substances |
| solution | a mixture in which one or more substances are evenly distributed in another substance |
| acids | compounds that form hydrogen ions when dissolved in water |
| bases | compounds that reduce the concentration of hydrogen ions in a solution |
| carbohydrates | organic compounds made of carbon, hydrogen, and oxygen atoms in the proportion of 1:2:1 |
| monosaccharides | the single sugars that are building blocks of carbohydrates |
| lipids | nonpolar molecules that are not soluble in water |
| protein | a chain of molecules called amino acids linked together |
| amino acids | the building blocks of proteins |
| nucleic acid | a long chain of smaller molecules called nucleotides |
| nucleotide | has three parts: a sugar, a base, and a phospate group, which contains phosphorus and oxygen atoms; there are two types of nucleic acids: DNA and RNA |
| DNA | double-stranded, helical nucleic acid that stores hereditary information |
| RNA | a type of nucleic acid involved in protein synthesis |
| ATP | organic molecule composed of a base, a sugar, and three phosphate groups that acts as the main energy currency of cells |
| energy | the ability to move or change matter |
| activation energy | the energy needed to start a chemical reaction |
| enzymes | substances that increase the speed of chemical reactions |
| substrate | a substance on which an enzyme acts during a chemical reaction |
| active sites | site on an enzyme that attaches to a substrate |
