| The link reaction | - Pyruvate mol produced by glycolysis AT into matrix of mitochondria from cytoplasm
- Pyruvate undergoes series of reactions |
| Changes to the pyruvate | - Pyruvate oxidised to acetate
- Pyruvate loses a CO2 mol + 2 Hs
- These Hs are accepted by NAD to form NADH2, which is later is used to produce ATP
- 2 C acetate combines with CoA to produce acetyl CoA |
| The link reaction equation | pyruvate + NAD + CoA .-----> acetyl CoA + reduced NAD + CO2 |
| The Krebs cycle | - Series of oxidation-reduction reactions
- Matrix of the mitochondria |
| The events of the Krebs cycle | - AcetylcoA from LR combines with a 4 C mol to produce a 6 C mol
- CoA goes back to LR to be used again
- Citrate (6c) converted to 5 C mol
- Decarboxylation occurs, CO2 removed
- Dehydrogenation occurs, H removed
- The H used to produce NADH2 |
| For each molecule of pyruvate, the link reaction and the Krebs cycle therefore produce.... | - Reduced NAD + FAD
- Have potential to provide energy to produce ATP molecules by oxidative phosphorylation
- Important products of Krebs
- 1 molecule of ATP
- 3 molecules of CO2 |
| Coenzymes | - NOT ENZYMES
- Molecules that some enzymes require in order to function
- Major role in photosynthesis + respiration where they carry hydrogen atom form 1 molecules to another |
| Exaples of coennzymes | - NAD, important throughout respiration
- FAD, important in Krebs cycle
- NADP, important in photosynthesis |
| NAD in respiration | - Works with dehydrogenase enzymes that catalyse the removal of H2 atoms from substrates
- Transfers them to other molecules involved in oxidative phosphorylation |
| The significance of the Krebs cycle | - Pyruvate is broken down into CO2
- Produces H2 that is carried by NAD to the ETC + provide energy for oxidative phosphorylation
- Leads to the production of ATP that provides metabolic energy for the cell
- Regenerates the 4 C molecule that combines with acetylco A, which would otherwise accumulate
- Source of intermediate compounds used by cells in the manufacture of fatty acids, amino acids + chlorophyll |
