Plants and Photosynthesis

Plants are extraordinary because they can make their own food — no trips to the supermarket needed! Animals must eat to get energy, but plants build their own food using nothing more than sunlight, air and water. This amazing process is called photosynthesis.

Photosynthesis mostly happens inside the leaves. A plant takes in a gas called carbon dioxide from the air through tiny holes in its leaves called stomata. At the same time, it draws up water from the soil through its roots and up the stem.

Using the energy captured by chlorophyll from sunlight, the plant combines the carbon dioxide and water to make a sugar called glucose. Glucose is the plant's food — it uses it for energy and to grow. As a by-product, the plant releases oxygen back into the air.

Each part of the plant has an important job in photosynthesis. The roots absorb water and anchor the plant. The stem carries water up and holds the leaves towards the light. The leaves are broad and flat to catch as much sunlight as possible, and they contain the chlorophyll.

Plants are the start of nearly every food chain. They are called producers because they produce their own food. Animals that eat plants get that stored energy, and animals that eat those animals get it too. So the energy in a lion ultimately came from the Sun, captured by grass.

A common misunderstanding is that plants get their food from the soil. They do not — they MAKE their food by photosynthesis. From the soil they only take water and a few mineral nutrients, such as nitrogen, which they use to grow strong and healthy. Fertilisers add these minerals back when the soil runs low.