Photosynthesis Explained Simply

Steps

1. Light energy from the sun is absorbed by chlorophyll, the green pigment in plant cells, primarily in structures called chloroplasts.
2. Water absorbed by the roots travels up to the leaves, while carbon dioxide enters the leaves through tiny pores called stomata.
3. In the light-dependent reactions, light energy splits water molecules into hydrogen and oxygen, releasing oxygen gas as a byproduct that exits through the stomata.
4. In the light-independent reactions (Calvin cycle), the hydrogen combines with carbon dioxide using energy captured earlier to build glucose molecules.
5. The glucose produced is used by the plant for energy and growth, or stored for later use as starch.

Worked example

When a sunflower plant performs photosynthesis on a sunny day, it absorbs 6 molecules of carbon dioxide and 6 molecules of water. Using light energy, it produces 1 molecule of glucose (C6H12O6) and releases 6 molecules of oxygen into the air. The chemical equation is: 6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

Remember

Photosynthesis converts sunlight, carbon dioxide, and water into glucose and oxygen, making it essential for plant growth and for producing the oxygen we breathe.