M2 L11-12 Flashcards
Energy from Glucose (aerobic metabolism to pyruvate, the pyruvate dehydrogenase reaction) and the citric acid cycle
Outline the pyruvate dehydrogenase reaction and describe its importance
it is a reaction where it turns pyruvate into Acetyl-CoA and NADH and CO2. it is important to make sure that the cell respiration continues and the citric acid cycle can start
Explain the importance of the citric acid cycle in metabolism of pyruvate
the citric acid cycle makes Acetyl CoA into citrate and then into oxaloacetate so it can become Acetyl CoA again, making 1 ATP per molecule of Acetyl CoA, 2 NADH, 1FADH2 and 2 CO2
Explain the importance of the citric acid cycle in providing intermediates for other pathways
the intermediates will be used to maintain blood glucose levels and are essential to the cell, they are used to synthesize amino acids, they make them essential to life
Describe the pyruvate carboxylase reaction and explain why it is metabolically important.
it converts pyruvate and CO2 to oxaloacetate, helps restart the citric acid cycle, helps replenish the intermediates
Outline the regulation of the citric acid cycle
ADP activates the isocitrate pyruvate enzyme to increase the flux, key irreversible reactions are the key control points.
Isocitrate dehydrogenase and ɑ-ketoglutarate dehydrogenase (CA2+) increases the activity of these enzymes, calcium also increases the activity of pyruvate dehydrogenase, calcium is flooded in a cell to contract the muscle in anticipation that ATP will be needed shortly
explain pyruvate dehydrogenase insufficiency
If the phosphatase is not fully functional or only able to operate at very slow rates, the PDH enzyme will remain phosphorylated, and hence inactive.
outline the bioenergetics of glycolysis in anerobic conditions
it produces 2 pyruvate that turn into two lactate, and also producing 2 ATP, 2 NAD+ that turns into 2 NADH that turns again into 2 NAD+ so it can repeat
Describe the transport of pyruvate from cytosol to mitochondrion
it is transported by an antiport membrane transport protein in exchange for OH, it then goes into the mitochondrial matrix
describe how 1080 can be deadly
sodium fluoroacetate will get in the cell and an enzyme will see it as an acetate group and use it in the CA Cycle, it is then converted to fluorocitrate by Acetyl CoA synthetase, it is a substrate for citrate synthase, the aconitase binds to fluorocitrate and it inhibits it so the cycle does not continue, blocks the cell from making more ATP which leads to death
Write the equation for the pyruvate dehydrogenase reaction that connects glycolysis to the tricarboxylic acid cycle
pyruvate + CoA-SH + NAD+ –> Acetyl-S-CoA + CO2 + NADH + H+
