| Term | Definition |
| cell | basic unit of structure and function in living things |
| theory | idea that explains something and is supported by data |
| cell membrane | thin structure that surrounds a cell |
| cytoplasm | all the living material inside a cell except the nucleus |
| nucleus | control center of a cell |
| mitochondria | rice-shaped structures that produce energy for a cell |
| organelles | small structures in the cytoplasm that do special jobs |
| ribosomes | small round structures that make proteins |
| vacuoles | liquid-filled spaces in the cytoplasm |
| cellulose | hard, nonliving material that makes up the cell wall of a plant cell |
| cell wall | outer, nonliving part of a plant cell |
| chlorophyll | green material in chloroplasts that is needed for plants to make food |
| chloroplast | green structure in a plant cell that contains chlorophyll |
| diffusion | movement of material from an area where molecules are crowded to an area where they are less crowded |
| osmosis | movement of water through a membrane |