Plants are able make their own food using only carbon dioxide, water, and the energy from sunlight.
This chemical reaction is called photosynthesis and it supports all other complex life on Earth.
Every leaf is a solar-powered food factory, producing the food a plant requires from simple ingredients: water and carbon dioxide.
Water enters the plant via root hair cells and travels up to the leaves in tubes called xylem.
Water – transported to leaves in xylem
Carbon dioxide from the atmosphere enters the leaf through tiny holes called stomata.
Carbon dioxide – enters leaves through stomata
It is here in the chloroplasts, tiny cellular bags filled with chlorophyll, that photosynthesis occurs.
Chlorophyll is key: it traps energy from the Sun and uses it to bond carbon dioxide from the air to hydrogen from the water.
Carbon dioxide from air
Hydrogen from water
This process produces glucose, which is used for the plant's growth and stored as starch.
A waste gas – oxygen – is produced.
Like carbon dioxide, oxygen is exchanged through the stomata.
Photosynthesis is a simple equation.
Carbon dioxide + water + light
→ glucose + oxygen
Without this essential process, plants couldn't grow.
And if plants couldn't grow and reproduce, other organisms would have nothing to eat.
Plants are the basis of the global food chain.
Plants' consumption of carbon dioxide, and production of oxygen by photosynthesis, is what creates our life-sustaining atmosphere.
Which is why photosynthesis is perhaps the most important chemical reaction of all.