How Does Photosynthesis: Light Reactions and the Calvin Cycle Work?

Photosynthesis is how plants turn sunlight into food using water and carbon dioxide.

Imagine a plant is like a chef in a kitchen. The light reactions are like the chef’s morning routine, they happen when the sun shines on the leaves. These reactions use light to split water into oxygen and hydrogen, like opening a bottle of water and making bubbles that float up as oxygen.

Then comes the Calvin Cycle, which is like the chef’s cooking time. It uses the hydrogen from the water and carbon dioxide from the air to make glucose, a kind of food. This happens even when it's dark, so it’s like the chef keeps working in the background while you're playing.

Think of the plant as a factory that takes in sunlight, water, and carbon dioxide, then makes sugar, its energy source, and gives out oxygen for us to breathe. The light reactions are the bright part of the work, while the Calvin Cycle is the steady, behind-the-scenes cooking. Together, they make sure plants have enough food all day long!