Krebs Cycle Flashcards Preview

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Flashcards in Krebs Cycle Deck (10):

what part of the cell does Krebs cycle take place?

in the mitochondrial matrix


the final products are



reaction 1: citrate
(citrate synthase)

it is a condensation reaction between acetyl-CoA with oxaloacetate to form citrate
citrate synthase enzyme catalyzes the reaction by joining oxalocacetate with acetyl-CoA and then a water molecule attacks the acetyl lead to release coenzyme A from the complex and H+ is released


reaction 2: isocitrate

it is the formation of isocitrate through the rearrangement of citrate
acontinase enzyme is used to remove a water molecule from citrate to be put on another location to yield isocitrate


reaction 3: alpha-ketoglutarate
(isocitrate dehydrogenase)

it is the oxidation of isocitrate into alpha-ketoglutarate
isocitrate dehydrogenase enzyme catalyzes the -OH group and hydrogen on C4 to yield an intermediate (oxalosuccinate) which has a generation of NAD+ to NADH + H+ and then loses a CO2 molecule to yield the alpha-ketoglutarate


reaction 4: succinyl-CoA
(alpha-ketoglutarate dehydroenase)

it is the oxidation of alpha-ketoglutarate to form succinyl-CoA
alpha-ketoglutarate dehydrogenase enzyme is used to reduced another NAD+ to NADH, have CO2 removed, and have coenzyme A added to form the 4-carbon compound, succinyl-CoA


reaction 5: succinate
(succinyl-CoA synthetase)

it is the conversion of succinyl-CoA to produce succinate
succinyl-CoA synthetase enzyme catalyzes the reaction by removing CoA, which allows for energy release to be used to make GTP from GDP + phosphate (Pi) by substrate-level phosphorylation
*GDP is used to make ATP


reaction 6: fumarate
(succinate dehydrogenase)

it is the oxidation of succinate into fumarate
succinate dehydrogenase enzyme is used to catalyze the removal of two hydrogens from succinate and for the reduction of FAD to FADH2


reaction 7: malate

it is the hydration (reversible) of fumarate into L-malate
fumarase enzyme catalyzes this reaction by a rearrangement process from adding hydrogen and oxygen back into the substrate that had been previously removed


reaction 8: oxaloacetate
(malate dehydrogenase)

it is the oxidation of malate to produce oxaloacetate
malate dehydrogenase enzyme is used to catalyze the process of making the starting product of krebs cycle and also reduced NAD+ to NADH and H+
the new oxaloacetate is used to renter the cycle?