International A Level Biology / Photosynthesis

Cyclic and non-cyclic photophosphorylation

Edexcel International A Level Biology (YBI11), chapter 14: Photosynthesis, specification point 5.3. Part of the full course.

Read the revision notes · International A Level Biology past papers

Cyclic photophosphorylation uses light energy to make ATP, with electrons returning to photosystem I. Comparing it with the non-cyclic route explains why plants need an extra source of ATP for the Calvin cycle.

More lessons in Photosynthesis

• Photosynthesis: the overall reaction
• ATP: the immediate energy supply
• Chloroplast structure and function
• Absorption and action spectra
• Separating leaf pigments by chromatography
• The light-dependent reactions
• The Calvin cycle
• What the plant makes from GALP
• Core practical 10: measuring the rate of photosynthesis
• Limiting factors: light, carbon dioxide, temperature and wavelength