Science & Earth · Updated September 2026
Photosynthesis explained
Photosynthesis is how green plants make sugar from carbon dioxide, water and light. The usual equation, why leaves are green, and why animals depend on it.
Photosynthesis is the process green plants, algae and some bacteria use to store the Sun’s energy in sugar. Carbon dioxide and water go in; glucose and oxygen come out. That oxygen is why animals can breathe.
The classroom equation is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (light and chlorophyll required). Chlorophyll is the green pigment that captures light. It reflects green, so most leaves look green.
Two big stages appear in higher-school texts: light-dependent reactions (in thylakoid membranes) and the Calvin cycle (in the stroma). You do not need those names for a basic search — you do need “light, water, CO₂, sugar, oxygen.”
Photosynthesis explained — key facts (2026)
| Topic | Fact |
|---|---|
| Who does it | Plants, algae, cyanobacteria |
| Inputs | Carbon dioxide, water, light |
| Outputs | Sugar (glucose) and oxygen |
| Pigment | Chlorophyll |
| Organelle in plants | Chloroplast |
| Gas plants take in (day) | CO₂ |
| Gas plants release (day) | O₂ |
| Why it matters | Base of most food chains and Earth’s oxygen |
Figures are the usual classroom and news-desk numbers for 2026. Border disputes and membership votes can change a count by one or two.
People also ask
What is the photosynthesis equation?
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ in the presence of light and chlorophyll.
Do plants photosynthesise at night?
The light reactions need light. Plants still respire at night, which uses oxygen — the reverse-looking part that confuses students.
Why are leaves green?
Chlorophyll absorbs red and blue light better than green, so green is reflected.