Summary OCR A-Level Biology 5.7.4 Krebs Cycle

Krebs Cycles
Stages of Krebs Cycle
 Acetyl CoA (2C) from the Link Reaction enters the cycle and joins with oxaloacetate (4C)
to from a 6-carbon compound, citrate (6C)
 Citrate is decarboxylated and dehydrogenated to release CO₂ and reduce NAD to NADH
and forms a 5-carbon compound
 5 carbon compound is further decarboxylated and dehydrogenated to release CO₂ and
reduce NAD to NADH and forms a 4 carbon compound
 Substrate level phosphorylation takes place and produces a molecule of ATP from the 4-
carbon compound, forming a different 4 carbon compound
 4-carbon compound is dehydrogenated to reduce FAD to FADH and form another 4
carbon compound
 4-carbon compound is dehydrogenated to reduce NAD to NADH and form oxaloacetate