Cell respiration 8.2 HL

This topic looks at the details of glycolysis, the link reaction and the krebs cycle.  The structure of mitochondria is related to its function and the amazing process of chemiosmosis is outlined leading to the production of water and ATP.


Key words

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Clean sweep - quick revision through the whole topic

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Structured question about cell respiration

Explaining the link reaction is an important skill from this topic.

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Compare and contrast the link reaction and the krebs cycle . [2]

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Revision summary list for 8.2 Respiration

Introduction to reactions in respiration

  • Cell respiration involves:
  • the oxidation and reduction of electron carriers.
  • the phosphorylation of molecules which makes them less stable.
  • decarboxylation removes a carbon atom from a molecule

Glycolysis & the Krebs cycle

  • Glycolysis is the conversion of glucose to pyruvate in the cytoplasm giving a small net gain of ATP(without the use of oxygen.)
  • Aerobic cell respiration converts the pyruvate by decarboxylation and oxidation, into an acetyl compound.
  • In the link reaction acetyl is attached to coenzyme A to form acetyl coenzyme A.
  • In the Krebs cycle,
    • the oxidation of acetyl groups is coupled to the reduction of hydrogen carriers, liberating carbon dioxide.
    • reduced NAD and FAD (NADH+H+ and FADH+) carry energy released by oxidation reactions to the cristae of the mitochondria.

The electron transport chain & Mitochondrion structure.

  • the electron transport chain in the membrane of the cristae is coupled to proton pumping.
  • oxygen is the final electron acceptor.
  • In chemiosmosis protons diffuse through ATP synthase to generate ATP.
  • Oxygen binds with the free protons to maintain the hydrogen gradient and resulting in the formation of water.
  • The structure of the mitochondrion is adapted its function. Annotate a diagram of a mitochondrion to show these adaptations

Skills

  • Active mitochondria have been studies using electron tomography - images.
  • students will be able to identify where decarboxylation and oxidation reactions occur in diagrams of the pathways of aerobic respiration.
  • Guidance:
  • The names of the intermediate compounds in gylcolysis and the Krebs cycle are not required.

Revision mindmap

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Review questions

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