Essential Idea:
Energy is converted to a
usable form in cell respiration
Understandings:
- Cell respiration involves the oxidation and reduction of electron carriers
- Phosphorylation of molecules makes them less stable
- In glycolysis, glucose is converted to pyruvate in the cytoplasm
- Glycolysis gives a small net gain of ATP without the use of oxygen
- In aerobic cell respiration pyruvate is decarboxylated and oxidised, and converted into acetyl compound and attached to coenzyme A to form acetyl coenzyme A in the link reaction
- In the Krebs cycle, the oxidation of acetyl groups is coupled to the reduction of hydrogen carriers, liberating carbon dioxide
- Energy released by oxidation reactions is carried to the cristae of the mitochondria by reduced NAD and FAD
- Transfer of electrons between carriers in the electron transport chain in the membrane of the cristae is coupled to proton pumping
- In chemiosmosis protons diffuse through ATP synthase to generate ATP
- Oxygen is needed to bind with the free protons to maintain the hydrogen gradient, resulting in the formation of water
- The structure of the mitochondrion is adapted to the function it performs
Applications:
- Electron tomography used to produce images of active mitochondria
Skills:
- Analysis of diagrams of the pathways of aerobic respiration to deduce where decarboxylation and oxidation reactions occur
- Annotation of a diagram of a mitochondrion to indicate the adaptations to its function