BRAINCAKE

Photosynthesis

Edexcel A-level BiologyTopic 2 of 1620 lessons

Revision notes for Photosynthesis in Edexcel Biology (9BI0). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.

  1. Autotrophs and HeterotrophsAll organisms need organic molecules, both as a source of energy and as building materials.
  2. The Process of PhotosynthesisPhotosynthesis is the process in which light energy is absorbed by chlorophyll and used to make organic molecules from carbon dioxide and water.
  3. ChloroplastsChloroplasts are the organelles in which photosynthesis takes place.
  4. ChlorophyllChloroplasts contain several photosynthetic pigments, molecules that absorb particular wavelengths of light.
  5. Absorption Spectrum ChlorophyllAn absorption spectrum is a graph showing how much light a pigment absorbs at each wavelength.
  6. ChromatographyPhotosynthetic pigments can be separated and identified by chromatography, using paper or a thin-layer chromatography (TLC) plate.
  7. PhotosystemsIn the thylakoid membranes, pigment molecules are not scattered randomly.
  8. The Light-Dependent ReactionsThe light-dependent reactions take place on the thylakoid membranes of the chloroplast.
  9. Cyclic PhotophosphorylationCyclic photophosphorylation is a pathway of electron flow in the light-dependent reactions that involves only photosystem I.
  10. Non-Cyclic PhotophosphorylationNon-cyclic photophosphorylation is the main pathway of the light-dependent reactions.
  11. The Light-Independent StageThe light-independent reactions are the second stage of photosynthesis.
  12. The Calvin CycleThe Calvin cycle is the series of enzyme-controlled reactions in the stroma that fixes carbon dioxide into carbohydrate.
  13. The Products of PhotosynthesisThe main product of the Calvin cycle is GALP (glyceraldehyde 3-phosphate), a triose phosphate.
  14. C4 PlantsIn most plants, called C3 plants, the first product of carbon fixation is GP, a 3-carbon compound.
  15. RubiscoRUBISCO (ribulose bisphosphate carboxylase-oxygenase) is the enzyme in the stroma that fixes carbon dioxide in the Calvin cycle.
  16. Limiting Factors of PhotosynthesisThe rate of photosynthesis depends on several external factors.
  17. LightLight is the energy source for the light-dependent reactions in the thylakoid membranes.
  18. Carbon DioxideCarbon dioxide is a substrate of the light-independent reactions (the Calvin cycle) in the stroma.
  19. TemperatureTemperature affects photosynthesis mainly through enzymes.
  20. Limiting Factors in the WildIn a laboratory, one factor is changed while the others are held constant.

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