Photosynthesis
Photosynthesis is the process by which plants use light energy to turn carbon dioxide and water into glucose and oxygen.
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Photosynthesis is the process by which plants use light energy to turn carbon dioxide and water into glucose and oxygen.
- Takes place in chloroplasts
- Chlorophyll absorbs light
- Carbon dioxide plus water gives glucose plus oxygen
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Photosynthesis?
Within Biology, which covers cells, the human body, genetics, evolution, plants and ecosystems: the science of living things, this topic explains Photosynthesis. Biology topics show how living things work, from the cell up to whole ecosystems, with models you can explore step by step.
Check that you can explain Photosynthesis in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Photosynthesis helps you explain how living things stay alive and respond to their surroundings, which is central to biology exams.
Photosynthesis in detail
Photosynthesis is the process by which plants, algae and some bacteria make glucose using light energy. The word equation is carbon dioxide + water → glucose + oxygen, and the balanced equation is 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. It takes place in chloroplasts, which contain the green pigment chlorophyll that absorbs light.
It is an endothermic reaction, because it takes in energy. Glucose is used for respiration, converted to starch for storage, to cellulose for cell walls, to fats and oils or to proteins with nitrates. Photosynthesis produces the oxygen in the air and is the base of almost all food chains.
How the interactive helps you understand Photosynthesis
Watch the cycle in the interactive. Use any sliders or buttons it offers to change the values and see how the cycle responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Photosynthesis.
Real-life uses and examples
- Use Photosynthesis to interpret a diagram, graph or microscope image from a practical.
- Structure a longer answer about Photosynthesis by moving from definition to example to consequence.
- Explain how Photosynthesis helps a living thing stay alive, using a plant or animal example.
Common mistakes to avoid
- Using everyday words, such as “energy” or “bad”, without their scientific meaning.
- Listing the steps of a process without saying how one step causes the next.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Photosynthesis
What is Photosynthesis?
Photosynthesis is the process by which plants use light energy to turn carbon dioxide and water into glucose and oxygen.
What are the most important points about Photosynthesis?
The main points are: Takes place in chloroplasts; Chlorophyll absorbs light; Carbon dioxide plus water gives glucose plus oxygen.
Why is Photosynthesis useful?
Understanding Photosynthesis helps you explain how living things stay alive and respond to their surroundings, which is central to biology exams.
How can I practise Photosynthesis?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Photosynthesis?
Related topics in Biology include Transport in Plants, Reproduction in Flowering Plants, Anaerobic Respiration.