The leaves are where plants do most of their photosynthesis. Carbon dioxide and oxygen enter and leave the leaves through tiny holes on the underside of the leaves. The holes are called “stomata” or little mouths. Inside the cells of the leaf, the plant uses energy from the sun to put carbon dioxide and water together to make sugar. Oxygen is a waste product.

A lot of people don’t know this, but the cell can also take apart the sugar to release energy. Then they give off carbon dioxide and water, just like us. If you think about it, they have to do this because only a part of the plant does photosynthesis, but all the plant cells need energy, even the cells in the roots. The sugar made in the leaves is sent to all the cells in the plant using the plant’s tube system.

Why do you think the leaf holes (stomata) close up on hot, dry days?

If questions like these interest you, you may want to study plant ecology.

Leaves are actually what the plant uses to undergo photosynthesis - which is the process by which light energy is used to make food (sugar) for the plant. During photosynthesis, carbon dioxide is absorbed and oxygen is released. Leaves are actually made up of millions of cells, each containing chloroplasts, which is a type of organelle (or mini organ). Chloroplasts contain the tools needed that help the plant to absorb light and transform it into sugar. Energy from light is used to change carbon dioxide (CO) and water (H₂O) into sugar (made up of carbon, oxygen, and hydrogen molecules) and during this process oxygen (O₂) is released.

Leaves open up tiny holes in the surface of the leaf (called 'stomata') to let the carbon dioxide into the leaf. They then take the energy from the sun to pull the carbon atoms out of the carbon dioxide. This leaves oxygen behind as a waste product, which then escapes out of the stomata the same way that the carbon dioxide entered.

Thanks for the great question!

Leaves are a part of a plant specially designed for changing light from the sun into food for the plant. This is called photosynthesis. This process changes sunlight and carbon dioxide into sugar for the plant and oxygen that is let back into the air.

Leaves have many adaptations that make them well designed for photosynthesis. The flat surface of the leaf contains many tiny openings called stomata. These are like very small holes that allow carbon dioxide into the leaf – and oxygen out. There can be over 100,000 stomata in an inch of a leaf!

Carbon dioxide inside the leaf is then used by a special part of the plant cell called the chloroplast. The main job of the chloroplast is to combine energy collected from sunlight with the carbon dioxide let in by the stomata. This creates food for the plant and also gives off oxygen, which is then released into the air.

Thanks for the question.