Krebs Cycle
Citric Acid Cycle
From Aerobic Respiration
Pyruvate is split to form CO2 and an acetyl group
The acetyl group attaches to CoA (Co-Enzyme A) to make acetyl CoA
Acetyl CoA enters the Mitochondria along with the NADH that was
produced from glycolysis
Citrate Synthase
Acetyl CoA donates its acetyl group to the four carbon molecule oxaloacetate
by using water
in order to form citrate
Yielding an isomer
H2O donates a Hydrogen to the released CoA molecule
and oxygen to the citrate.
Citrate is then converted into isocitrate by the enzyme aconitase.
Isocitrate Dehydrogenase
Isocitrate forms Alpha-ketoglutarate
2 electrons and a H+ are captured by NAD+ to make NADH
Alpha-Ketoglutarate forms succinate by releasing CO2
Alpha-ketogluterate dehydrogenase
Apha-ketogluterate is then converted into succynl-CoA
2 new energetic electrons and a H+ are captured by another NAD+ to make
another NADH
At this point all 3 carbons from the pyruvate have been released as CO2
Succynl-CoA Synthetase
Succynl-CoA is then converted into succinate
which yields 1 ATP per succynl-CoA
Enzyme Succinate Dehydrogenase
Succinate coverts into fumerate
FAD is reduced to FADH2 (a prosthetic group of succinate dehydrogenase).
Succinate dehydrogenase (electron carrier II) is a direct part of the ETC.
Hydration with the use of Fumerase
Fumerate is then converted to malate
by adding 2 hydrogens and 1 oxygen from H2O
Malate Dehydrogenase
Malate is converted into oxaloacetate
2 more energetic electrons and a H+ are captured by NAD+ to make another
NADH
Oxaloacetate (final metabolite of the Kreb Cycle) joins again to start the
cycle over again
In the end
A total of 10 NADH and 2 FADH2 (main source of ATP) have been created
The NADH and FADH2 are going to transport H+ through the mitochondrial
matrix in order to create a H+ concentration gradient.
Through the process of chemiosmosis the H+ are going to push through
the ATP synthase generating the majority of ATP.