| A | B |
|---|
| Bacteria | Smallest organisms on Earth, each of which is made only of one cell. |
| Cell Membrane | Flexible structure; holds a cell together; boundary between cell and environment; controls what enters and leaves the cell. |
| Cell Wall | Structure of plants, fungi, algae, and many bacteria that supports and protects the cell membrane. |
| Cytoplasm | Gelatinlike substance inside the cell membrane that contains water, chemicals, and cell parts. |
| Organelle | Specialized cell parts that perform a cell's activities. |
| Nucleus | Cell organelle that contains hereditary material. Controls cell function. |
| Vacuole | Balloonlike organelle in cytoplasm that can store, food, water, and other substances. |
| Mitochondria | Cell organelles where cellular respiration takes place. |
| Photosynthesis | Process where plants, algae and many types of bacteria use sunlight, water, and carbon dioxide to make food and oxygen. |
| Chloroplast | Green organelle in a plant's leaf cells where most photosynthesis takes place. |
| Tissue | Group of similar cells that do the same work. |
| Organ | Structure made of two or more tissue types that work together to do a certain job. |
| Organ System | Group of organs that work together to do a certain task. |
