| A | B |
|---|
| atom | smallest unit of matter that cannot be broken down by chemical means |
| element | substance made of only one kind of atom |
| compound | substance made of the joined atom of two or more different elements |
| molecule | group of atoms held together by covalent bonds |
| ion | 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 | mixture in which one or more substances are evenly distributed in another substance |
| acid | hydrogen ions form when dissolved in water |
| covalent bond | chemical bond in which electrons are shared |
| ionic bond | attraction between oppositely charged ions |
| substrate | substance on which an enzyme acts during a chemical reaction |
| monosaccharide | an example is glucose which is a major energy source in cells |
| lipid | an organic compound that is not soluble in water |
| protein | a long chain of amino acids |
| nucleotides | subunits of DNA and RNA; sugar, phosphate and base |
| enzyme | a protein that speeds up a chemical reaction |
| active site | location on an enzyme that binds to a substrate |
| base | reduce the number of hydrogen ions when dissolved in water (form OH) |
| activation energy | the energy needed to start a chemical reaction |
| ATP | energy currency of the cell |
| carbohydrate | organic molecules that act as a source of energy |
