| A | B |
|---|
| sensitivity | responsiveness of an organ or organism |
| metabolism | physical and chemical changes in an organism in which energy is released or used |
| homeostasis | tendency to maintain stability in an organism amid environmental change |
| heredity | transmission of characteristics from parent to offspring by means of genes on the chromosome |
| atom | smallest unit of matter that cannot be broken down by chemical means |
| element | matter that is made of only one kind of atom |
| electron | elementary particle with negative electric charge |
| ion | an atom that has lost or gained one or more electrons and therefore has a net electric charge |
| chemical bond | attractive force that holds two atoms together in a molecule |
| ionic bond | force of attraction between oppositely charged ions |
| covalent bond | non-ionic chemical bond formed by shared elctrons |
| molecule | group of atoms that form the smallest unit of a substance that can exist and retain its chemical properties |
| macromolecule | large molecule composed of several simple structural units, such as DNA or proteins |
| organic compound | compound containing the element carbon |
| carbohydrate | compound composed of carbon, hydrogen and oxygen, used by living things as a source of energy |
| lipid | organic compound containing fats, alcohol and waxes that organisms may use to store energy |
| protein | any of the polymers of amino acids |
| nucleic acid | DNA or RNA; large chainlike molecule containing phosphoric acid, sugar, and purine and pyrimidine bases |
| nucleotide | structural unit of a nucleic acid (subunit of DNA or RNA) consisting of three parts: a sugar, a phosphate group, and a base |
| chromosome | threadlike structure formed in the cell during prophase of mitosis that contains DNA |
