Doc Brown's GCSE OCR 21st Century Science-Biology Revision Notes

PLEASE NOTE NEW revision summaries for the NEW OCR 21st Century Science B GCSE Biology B and NEW OCR GCSE 21st Century Combined Science B Biology courses: Revision for Chapters 1-3) and  Paper 2 (Chapters 4-6) STARTING with Y10 in Sept. 2016 onwards, first exams in 2018

OCR GCSE 21st Century Additional Science Biology Module B4 The processes of life

Unit B4.1 How do chemical reactions take place in living things?

  • 1. understand that the basic processes of life carried out by all living things depend on chemical reactions within cells that require energy released by respiration

  • 2. understand the role of photosynthesis in making food molecules and energy available to living organisms through food chains.

  • 3. be able to describe photosynthesis as a series of chemical reactions that use energy from sunlight to build large food molecules in plant cells and some microorganisms (eg phytoplankton)

  • 4. be able to describe respiration as a series of chemical reactions that release energy by breaking down large food molecules in all living cells

  • 5. know that enzymes are proteins that speed up chemical reactions

  • 6. know that cells make enzymes according to the instructions carried in genes

  • 7. understand that molecules have to be the correct shape to fit into the active site of the enzyme (the lock and key model)

  • 8. understand that enzymes need a specific constant temperature to work at their optimum, and that they permanently stop working (denature) if the temperature is too high

  • 9. HT only: be able to explain that enzyme activity at different temperatures is a balance between:

    • a) increased rates of reaction as temperature increases

    • b) changes to the active site at higher temperatures, including denaturing

      • You are not expected to explain why rates of reaction increase with temperature here

  • 10. know that an enzyme works at its optimum at a specific pH

  • 11. HT only: be able to explain the effect of pH on enzyme activity in terms of changes to the shape of the active site.

  • Revision Notes



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