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Energy for Biological Processes

OCR A-level BiologyTopic 6 of 1217 lessons

Revision notes for Energy for Biological Processes in OCR Biology A (H420). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.

  1. ATPATP is the universal energy currency in cells.
  2. ChloroplastsChloroplasts are the site of photosynthesis.
  3. Photosynthetic pigmentsThe main photosynthetic pigment in chloroplasts is the blue-green chlorophyll a.
  4. PhotosystemsPhotosynthetic pigments are arranged in light-harvesting clusters or photosystems in the thylakoid membrane.
  5. Cyclic PhotophosphorylationCyclic photophosphorylation is one of two light-dependent reactions and involves photosystem I only.
  6. Non-cyclic PhotophosphorylationNon-cyclic photophosphorylation involves both PSI and PSII.
  7. ChemiosmosisChemiosmosis is the synthesis of ATP driven by the flow of protons (H+) down a gradient across a membrane.
  8. Calvin CycleATP and reduced NADP from the light-dependent reactions are used in the Calvin cycle which is a light-independent process.
  9. Limiting Factors of PhotosynthesisThe rate of photosynthesis depends on several factors: light intensity, carbon dioxide concentration and temperature (water availability matters…
  10. Light Intensity as a Limiting FactorLight provides the energy for the light-dependent stage.
  11. Carbon Dioxide Concentration as a Limiting FactorCarbon dioxide is a substrate of the Calvin cycle.
  12. Temperature as a Limiting FactorTemperature affects the rate of photosynthesis mainly through the enzymes of the Calvin cycle, such as RuBisCO.
  13. Interpreting Limiting Factor GraphsExam questions often give a graph of rate of photosynthesis against one factor, with several curves for different levels of a second factor.
  14. Effect of Limiting Factors on the Calvin CycleThe levels of the three Calvin cycle intermediates, RuBP, GP and TP, change in predictable ways when a limiting factor changes.
  15. Uses of Triose PhosphateTriose phosphate (TP) is the 3-carbon product of the Calvin cycle, made when GP is reduced using ATP and reduced NADP.
  16. Investigating the Rate of PhotosynthesisThe rate of photosynthesis can be investigated by measuring the rate of oxygen production by an aquatic plant such as Elodea or Cabomba.
  17. Agricultural Glasshouses and Limiting FactorsCommercial growers use glasshouses (greenhouses) to control limiting factors, so crops photosynthesise faster, grow faster and give higher yields. •…

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