Flashcards in Carbohydrates 5 Deck (20)
Where does the citric acid cycle take place?
In the matrix of the mitochondria
Does the citric acid cycle produce ATP?
Yes but indirectly
Is O2 a reactant?
What is the citric acids action on electrons?
Removes them and passes them on to form NADH and FADH2
Why can't glycolysis yield all the potential energy from glucose?
In glycolysis there is no net oxidation of glucose because it is a redox reaction
Describe the effect of the evolutionary advantage in being able to use oxygen to oxidise food molecules?
Food molecules can be oxidised further than was possible before, allowed the complete breakdown of food molecules like glucose
What reaction in glycolysis requires NADH?
Pyruvate to lactate
Where is pyruvate oxidised into acetyl CoA?
In the mitochondrial matrix
Which enzyme is responsible for the conversion of pyruvate to acetyl CoA?
What does the carboxylation of Pyruvate result in the production of?
2 Hydrogen ions, can pass to O2 through NADH intermediates
Describe the enzyme pyruvate dehydrogenase
Massive, each sub-unit catalyses a different part of the reaction
Describe the changes in the number of intermediate molecules in the citric acid cycle
They remain constant
How do the two carbons that enter the cycle leave the cycle?
A 2 molecules of CO2
How is the activity of the enzyme pyruvate dehydrogenase regulated?
End product inhibition from Acetyl CoA, NADH, ATP
What are the other two control points of the citric acid cycle?
Isocitrate dehydrogenase - ATP and NADH negatively regulate, ADP positively regulates
Alpha - ketoglutarate dehydrogenase - ATP, NADH and succinyl CoA negatively regulate
They are both non-reversible reactions (exergonic)
What depletes the citric acid cycle of intermediates?
The production of nucleotide bases, heme groups and proteins.
The citric acid cycle is described as amphibolic, what does this mean?
It serves both catabolic and anabolic processes
What activity might deplete the cycle of oxaloacetate?
What does a build up of acetyl CoA trigger?
Pyruvate to Oxaloacetate, presence of AcetlyCoA causes the enzyme pyruvate carboxylase to become active