Link reaction and Krebs cycle

• 1. Give a definition of decarboxylation: The removal of a CO2 molecule from a molecule. This process requires the presence of oxygen.
• 1. Give a definition of dehydrogenation: The removal of hydrogen from an organic molecule.
• 1. Locations of the link reaction and Kreb's cycle: Mitochondrial matrix.
• 1. Describe what happens during the link reaction: The process in which pyruvate is converted into acetyl CoA via decarboxylating it and also dehydrogeing it via using NAD to accept the hydrogen forming reduced NAD. This forms a two carbon molecule Acetate in which reacts with coenzyme a to form acetyl coenzyme A.
• During the Kreb's cycle, Oxaloacetate reacts with acetyl coenzyme A to form citrate (6C).
• Citrate (6C) is decarboxylated and dehydrogenated with the presence of oxygen and NAD+, forming a molecule of reduced NAD, carbon dioxide and a 5 carbon intermediate.
• The process of decarboxylation and dehydrogenation is repeated, forming carbon dioxide, reduced NAD and a 4 carbon intermediate.
• The 4 carbon intermediate reacts with ADP to form ATP, as well as gets dehydrogenated to form reduced FAD and reduced NAD.
• The process of the Kreb's cycle in total forms 2 molecules of carbon dioxide, 1 molecule of ATP, 1 molecule of reduced FAD and 3 molecules of reduced NAD.
• 1. State the role of reduced NAD and reduced

  FAD: they are hydrogen acceptors and are used in the ETC.
•  Explain why the link reaction and Kreb's cycle can only occur if there is sufficient oxygen present: This is because decarboxylation occurs which is the removal of carbon this requires oxygen to be present to form carbon dioxide As a waste product.