Question

ii. During the transfer of acetyl CoA from the mitochondrion to the cytosol, malate will be generated in the cytosol. Although malate can be brought back into the mitochondrion directly, it will instead be converted into pyruvate which then enters the mitochondrion. Why does this happen?

1 point

a. The conversion of malate into pyruvate generates NADPH which can be used in fatty acid synthesis.

b. Movement of malate into the mitochondrion requires a lot of energy.

c. In the mitochondrion, the conversion of pyruvate into oxaloacetate requires less energy than the conversion of malate into oxaloacetate.

d. Pyruvate is smaller and moves faster into the mitochondrion.

What will happen to pyruvate in mitochondria when β-oxidation is active in the liver?

1 point

a. Aminated to produce alanine.

b. Oxidatively decarboxylated to acetyl CoA for oxidation in the citric acid cycle.

c. Reduced to lactate in the process of fermentation.

d. Carboxylated to oxaloacetate for entry into gluconeogenesis.

Answer 1

Ans1)a. The conversion of malate into pyruvate generates NADPH which can be used in fatty acid synthesis.

Explaination: The malate is oxidised by malic enzyme to produce pyruvate and CO2 along with generation of NADPH which is utilised  for lipogenesis process.

Ans2)b. Oxidatively decarboxylated to acetyl CoA for oxidation in the citric acid cycle.

Explaination: pyruvate undergo oxidative decarboxylation to produce acety coA and Co2 alongwith generation of NADH .this reaction is called link reaction between glycolysis and citric acid cycle and catalysed by pyruvate dehydrogenase complex. The resting acetylCoA enters into citric acid cycle and undergo oxidation.