| A | B |
|---|
| cell | basic unit of all living things |
| cell membrane | thin layer that surrounds all cells - allows water and dissolved materials to pass in and out of the cell |
| cell wall | tough outer covering of a plant cell that gives it a rigid shape - made of cellulose |
| nucleus | controls the cell's activities - important in cell reproduction |
| vacuole | large storage area that holds various substances, including food |
| cytoplasm | jellylike substance that fills much of the cell |
| chloroplasts | structures in which food making occurs - contain chlorophyll |
| outer bark | protective covering of a tree |
| heartwood | inner most part of a tree - made up of dried up layers of xylem |
| annual rings | result of growth each season |
| sapwood | living xylem cells that give the tree support and strength |
| cambium | thin growing layer of living cells |
