Summary OCR A-Level Biology 5.7.4 Link Reaction

Link Reaction
Stages of Link Reaction
 Pyruvate moves into the mitochondria by active transport
 0.5 ATP molecules used per 2 pyruvate molecules (1 glucose molecule)
 Pyruvate is dehydrogenated to reduces NAD to NADH
 Pyruvate is decarboxylated and Coenzyme A is added to make Acetyl CoA
 Catalysed by a large, multi-enzyme complex – pyruvate dehydrogenase



CoA
Pyruvate
NAD
NADH
CO₂
Acetyl CoA




Role of NAD
 NAD is reduced to NADH
 NAD⁺ + 2H⁻ NADH + H⁻
 redNAD carries protons and electrons to the mitochondria cristae to be used for
generation of ATP from ADP + P
 in Glycolysis, 2 NAD is reduced and accepts 2H⁻ ions allowing 2 Trios Phosphate to be
oxidised to form 2 Pyruvate
 In the Link Reaction, NAD is reduced and accepts a H⁻ ion allowing Pyruvate to be
oxidised