| A | B |
|---|
| cell | the basic unit of all living things |
| life processes | all the activities that enable an organizm to survive |
| metabolism | all the chemical changes that take place in a living thing |
| respiration | the process in which oxygen combines with food to release energy |
| oxygen | the key to releasing energy from food |
| Cell membrane | the outer covering of the cell |
| nuclear membrane | the outer covering of the nucleus |
| mitochondria | an organelle that converts the food into usable energy |
| endoplasmic reticulum | the transportation system of the cell |
| cell wall | the outer covering of a plant cell |
| chloroplast | the structure that contains chlorophyll |
| chlorophyll | the green substance that helps plants make their own food |
