Photosynthesis Lab

Photosynthesis Simulation: Light Reactions & Calvin Cycle

This photosynthesis simulation guides students through both stages of photosynthesis in chloroplasts: the light-dependent reactions in the thylakoid membrane, where chlorophyll absorbs photons to power electron transport and ATP and NADPH synthesis, and the Calvin cycle in the stroma, where those energy carriers are used to fix CO₂ into glucose. Learners can change light intensity, CO₂ concentration, and wavelength to observe how each variable affects the rate of photosynthesis. It is one of the most searched free biology simulations for middle school, high school, and AP Biology.

What you can do in this simulation

• Adjust light intensity and wavelength to see how chlorophyll absorption drives the electron transport chain
• Follow electrons from water splitting (photosystem II) through the electron transport chain to photosystem I
• Watch ATP synthase use the proton gradient to produce ATP via chemiosmosis
• Trace the Calvin cycle: CO₂ fixation by RuBisCO, reduction to G3P, and regeneration of RuBP
• Vary CO₂ concentration and light level to plot rate-limiting factors for overall photosynthesis

Concepts covered

light reactions · Calvin cycle · chlorophyll · electron transport chain · ATP synthesis · carbon fixation

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