| A | B |
|---|
| virus | a small, nonliving particle that invades and then reproduces inside a living cell |
| host | an organism that provides a source of energy or a suitable environment for a virus or another organism to live |
| parasite | an organism that lives on or in a host and causes harm to the host |
| bacteriophage | a virus that infects bacteria |
| cytoplasm | the region of a cell located inside the cell membrane (in prokaryotes) or between the cell membrane and nucleus (in eukaryotes); contains a gel-like material and cell organelles |
| ribosome | a tiny structure located in the cytoplasm of a cell where proteins are made |
| flagellum | a long, whiplike structure that extends out through the cell membrane and cell wall |
| binary fission | a form of asexual reproduction in which one cell divides to form two identical cells |
| asexual reproduction | the reproductive process that involves only one parent and produces offspring that are identical to the parent |
| sexual reproduction | the reproductive process that involves two parents who combine their genetic material to produce a new organism, which differs from both parents |
| conjugation | the process in which a unicellular organism transfers some of its genetic material to another unicellular organism |
| respiration | the process of breaking down food to release its energy |
| endospore | a small, rounded, thick-walled, resting cell that forms inside a bacterial cell |
| decomposer | an organism that breaks down large chemicals from dead organisms into small chemicals and returns important materials to the soil and water |
| infectious disease | an illness that can pass from one organism to another |
| toxin | a poison that can harm an organism |
| antibiotic | a chemical that can kill bacteria without harming a person's cells |
| vaccine | a substance that stimulates the body to produce chemicals that destroy viruses, bacteria, or other disease-causing organisms |
