Respiration

2026 Syllabus Objectives

By the end of this topic, you should be able to:

1. State where each of the four stages in aerobic respiration occurs in eukaryotic cells
2. Outline glycolysis as the phosphorylation of glucose and splitting of fructose 1,6-bisphosphate into two triose phosphate molecules, which are oxidised to pyruvate, producing ATP and reduced NAD
3. Explain that when oxygen is available, pyruvate enters mitochondria to take part in the link reaction
4. Describe the link reaction, including the role of coenzyme A in transferring acetyl groups
5. Outline the Krebs cycle, explaining how oxaloacetate accepts the 2C fragment from acetyl coenzyme A to form citrate, which is converted back to oxaloacetate
6. Explain that reactions in the Krebs cycle involve decarboxylation and dehydrogenation and the reduction of NAD and FAD
7. Describe the role of NAD and FAD in transferring hydrogen to carriers in the inner mitochondrial membrane
8. Explain the process of oxidative phosphorylation, including how hydrogen atoms split, electrons pass through the electron transport chain, protons are pumped across the membrane, and ATP is synthesized as protons return through ATP synthase
9. Describe the relationship between the structure and function of mitochondria
10. Outline respiration in anaerobic conditions in mammals (lactate fermentation) and yeast cells (ethanol fermentation)
11. Explain why the energy yield from aerobic respiration is much greater than from anaerobic respiration
12. Explain how rice is adapted to grow with roots submerged in water
13. Describe and carry out investigations using redox indicators to determine the effects of temperature and substrate concentration on yeast respiration
14. Describe and carry out investigations using respirometers to determine the effect of temperature on respiration rate