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Krebs Cycle Steps

For each molecule, describe what happens to it during Krebs Cycle

QuestionAnswer
Pyruvic Acid Enters the Krebs Cycle. Loses it's Carboxyl group by donating a H+ to NAD+ and releasing CO2. A CoA group is added to the remaining Acetyl group forming Acetyl~CoA (2C).
Acetyl~CoA (2C) The unstable CoA bond is broken - the Acetyle group joins Oxaloacetic acid (4C) to form one 6C compound: Citric Acid
Citric Acid (6C) Citric Acid is converted to its isomer: Isocitric Acid by the removal and then addition of a H2O molecule.
Isocitric Acid (6C) A Carboxyl group is lost by the release of CO2 and the reduction of NAD+ to NADH. a-Ketoglutaric acid remains (5C)
a-Ketoglutaric Acid (5C) A H+ is donated to NAD+ and a CO2 is released. An unstable CoA bond is added making Succynyl~CoA (4C)
Succynyl~CoA (4C) CoA is replaced by a Phosphate group which is then transferred to GDP+ and ultimately to ATP. The 4 Carbon Succinic Acid remains.
Succinic Acid (4C) 2 H+ are transferred to FAD to form FAD2. Fumaric acid remains (4C).
Fumaric Acid (4C) A H2O molecule is added, bonds are rearranged to form Malic Acid (4C)
Malic Acid (4C) NAD+ is reduced to NADH leaving Oxaloacetic Acid (4C)
Oxaloacetic Acid (4C) joins the Acetyl group of Acetyle~CoA while the CoA is lost forming Citric Acid.
How many ATPs are invested during Krebs Cycle? None
How many NADH are produced per original molecule of glucose? 6
How many FADH2 are produced per glucose? 2
How many turns of the Krebs Cycle occur for every glucose that went through glycolysis? 2
Created by: BiologyBee