| A | B |
|---|
| bacteria | smallest organisms on Earth, each of which is made up of only one cell |
| cell membrane | flexible structure that holds a cell together, forms a boundary between the cell and its environment, and helps control what enters and leaves the cell |
| cell wall | structure of plants, algae, fungi, and many types of 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 the hereditary material |
| vacuole | balloonlike cell organelle in the cytoplasm that can store food, water, and other substances |
| mitochondria | cell organelles where cellular respiration takes place |
| photosynthesis | process by which plants, algae, and many types of bacteria make their own food |
| chloroplast | green organelle in a plant's leaf cells where most photosynthsesis takes place |
| tissue | group of similar cells that all do the same work |
| organ | structure made of two or more different tissue types that work together to do a certain job |
| organ system | group of organs that work together to perform a certain job |
