The nucleus contains genetic information and controls the activities of the cell.
The cell membrane is partially permeable. It controls the movement of substances in and out of the cell.
The cytoplasm is a jelly-like substance that fills the cell. It contains cell parts and allows substances to move within the cell.
Plant cells have a cell wall. It is stronger and less flexible than the cell membrane. It supports the cell and gives it a regular shape.
Plant cells have chloroplasts. They contain chlorophyll which traps light for photosynthesis. Chloroplasts are found mainly in the cells of leaves and green stems.

Red blood cells do not have a nucleus. This gives them more space to carry and transport oxygen around the body.

Root cells do not have chloroplasts even though they are plant cells. Roots are usually found underground and do not receive sunlight. Unlike leaf cells, root cells cannot trap sunlight for photosynthesis.
Root hair cells have a protruding structure to increase the surface area exposed to the surrounding soil. This enables roots to absorb water and mineral salts at a faster rate.

Guard cells work in pairs to form the stoma. Stomata are mostly found on the underside of leaves, away from direct sunlight. The guard cells are able to open and close the stoma to control the rate of transpiration. On a hot and dry day, the stoma will become smaller to reduce water loss.

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