Plant cell organisation
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Explainer Video
Summary
Plant cell organisation
In a nutshell
Plant cells are organised into tissues and organs, just like animals. The leaf is the site of photosynthesis and gas exchange in plants.
Plants
In a plant, several organs work together and form an organ system. The leaves, stems and roots are all organs which work together to transport important substances around the plant. These plant organs are made from various tissues which have specific properties:
Tissue | Property |
| Xylem and phloem | These transport substances around the plant. ExamplesWater, minerals and food. |
| Palisade mesophyll tissue | This is where most photosynthesis occurs. It is a part of the leaf. |
| Spongy mesophyll tissue | This has large air spaces, allowing gases to diffuse into and out of the cells. It is also a part of the leaf. |
| Epidermal tissue | This covers the entire plant. |
| Meristem tissue | This is located at the growing tips of the roots and shoots. |
Leaf structure
The leaf is the site of photosynthesis and gas exchange in the plant. The structures of tissues in the leaf all have an important function:
| | Adaptation | Description |
| 1. | Transparent waxy cuticle | Also allows light to pass through to the chloroplasts. |
| 2. | Transparent epidermis cells | Allows light to pass through to the chloroplasts. |
| 3. | Tightly packed mesophyll cells | Palisade mesophyll cells are located at the top of the leaf and they contain lots of chloroplasts which maximises photosynthesis. |
| 4. | Spongy mesophyll | The spongy mesophyll contains air spaces (8.) which increase the rate of diffusion of gases. |
| 5. | Phloem | The phloem tubes transport the glucose that is made during photosynthesis away from the leaf. |
| 6. | Xylem | The xylem tubes transport water from the roots to the leaf for photosynthesis. |
| 7. | Stomata | These pores allow carbon dioxide to diffuse into the leaf from the air and oxygen to diffuse out of the cells. |
The leaf is also thin, this allows air to surround most of the cells. This means gas exchange can take place over a larger surface area.
FAQs - Frequently Asked Questions
Where does photosynthesis happen?
The leaf is the site of photosynthesis and gas exchange in the plant.
How does the upper dermis layer support photosynthesis?
This transparent layer allows light to enter the deeper leaf cells.
What organs are in a plant?
The leaves, stems and roots are all organs which work together to transport important substances around the plant.