Summary
Plants use light, water and carbon dioxide to make glucose and oxygen.
In depth
Overall: 6CO2 + 6H2O + light energy gives C6H12O6 + 6O2. It has light-dependent reactions (thylakoids) and the Calvin cycle (stroma). Oxygen comes from water, shown by isotope experiments.
Measure rate through oxygen release, CO2 uptake or biomass.
Light energy is converted to chemical energy in two linked stages. The light reactions make ATP and NADPH; the Calvin cycle uses them to fix CO2 into sugars. Only about 1 to 2 percent of incident light ends up as biomass.
Common mistake: photosynthesis does not occur only in the day or only in leaves; green stems and some other tissues also photosynthesise, but the light reactions need light.
Frequently asked questions
What is Photosynthesis?
Plants use light, water and carbon dioxide to make glucose and oxygen.
Which area of biology covers Photosynthesis, and how advanced is it?
Photosynthesis is one of the 56 topics in Plant Biology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Light-Dependent Reactions, Calvin Cycle, Rubisco.
Why does Photosynthesis matter?
Nearly all food chains and atmospheric oxygen depend on it.
What should I learn before Photosynthesis?
Photosynthesis is a Beginner topic, so no earlier topic is required. Other Beginner topics in Plant Biology that pair well with it include Plant Kingdom, Chlorophyll, Roots.
What topics are related to Photosynthesis?
The closest topics to Photosynthesis are Light-Dependent Reactions, Calvin Cycle, Rubisco, Stems. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Photosynthesis?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Photosynthesis. To practise the whole of Plant Biology, use the Plant Biology quiz.
How is Photosynthesis different from Light-Dependent Reactions?
Photosynthesis: Plants use light, water and carbon dioxide to make glucose and oxygen. Light-Dependent Reactions: In the thylakoid membranes, light splits water, releasing oxygen and making ATP and NADPH. Read both side by side and note what each one explains.
What is a common mistake about Photosynthesis?
Photosynthesis does not occur only in the day or only in leaves; green stems and some other tissues also photosynthesise, but the light reactions need light.
How should I study Photosynthesis step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Light-Dependent Reactions and explain the difference aloud. Finally, take the Plant Biology quiz and come back to this page for any question you miss.