Citric acid cycle Flashcards
What happens in cellular respiration?
Pyrucate is oxidized to H2O and CO2
What is the first step of cellular respiration?
Production of acetyl CoA
Under which conditions is glucose turned into Acetyl CoA?
Aerobic
Under which conditions does the citric acid cycle happen?
Aerobic
What is the second step of the cellular respiration?
Oxidation of acetyl groups to CO2 in the citric acid cycle
What is stage 3 of cellular respiration?
Electron transport chain and oxidative phosphorylation
What is the mitochondrial pyruvate carrier (MPC)?
H+ coupled pyruvate specific symporter
Where is the mitochondrial pyruvate carrier (MPC) found?
Inner mitochondrial membrane
Why is oxygen so important?
To regenerate NAD
Where are the two NAD pools located?
Cytoplasm
Mitochondria
What does the citric acid cycle oxidizes?
Acetyl CoA to CO2 and H2O
Most important allosteric regulartor
ATP and ADP
Different name for citric acid cycle
Krebs cycle
What is the citric acid cycle a source of?
Biosynthetic precursor
What is the fuel for citric acid cycle?
Acetyl CoA
Where does the citric acid cycle take place?
Matrix of mitochondria
What I s substrate channeling?
The passage of intermediates from one enzyme directly to another enzyme without release
What allows lipoamide to move between different active sites?
Flexible linkage
How many steps does the citric acid cycle have?
8
What is the first reaction of the citric acid cycle?
Citrate syntheses (formation of citrate)
What does citrate synthase catalyse?
Condensation of acetyl CoA with oxaloacetate to form citrate
What is the delta G of the first reaction in the citric acid cycle?
Very negative, pretty much irreversible
What kind of fit does citrate synthase exhibit?
Induced fit
What is the reaction intermediate of the first reaction of the citric acid cycle?
Citryl CoA
Is the second reaction of the citric acid cycle endergonic or exergonic?
Endergonic
Which enzyme is used in the second reaction of the citric acid cycle?
Aconitase
What does aconite catalyse?
The reversible transformation of citrate to isocitrate
What is the intermediate of the second reaction of the citric acid cycle?
Cis-aconitate
Which enzyme catalyses the third reaction in the citric acid cycle?
Isocitrate dehydrogenase
What catalysis the fourth reaction in the citric acid cycle?
Alpha-ketoglutarate dehydrogenase complex
What catalyses the fifth reaction of the citric acid cycle?
succinylcholine CoA synthetase
GTP + ADP <->
GDP + ATP
What catalyses the conversion of GTP and ATP
Nucleoside diphosphate kinase
What catalyses the sixth reaction of the citric acid cycle?
Succinate dehydrogenase
What is delta G of the sixth reaction of the citric acid cycle?
0
What catalyses the hydration of fumerate to L-malate?
Fumerase
What enzyme catalyses the seventh reaction of the citric acid cycle?
Fumerase
What enzyme catalyses the eighth reaction of the citric acid cycle?
Malate dehydrogenase
What can oxaloacetate do to initiate another cycle?
Condense with another acetyl CoA
What inhibits citrate synthase?
ATP
NADH
Citrate
Succinylcholine CoA
What stimulates citrate synthase?
ADP
What stimulates isocitrate dehydrogenase?
Calcium
ADP
What inhibits isocitrate dehydrogenase?
ATP
What inhibits alpha ketogluterate dehydrogenase?
Succinylcholine CoA
NADH
What stimulates alpha ketogluterate dehydrogenase?
Calcium