Question

The citric acid cycle is a critical sequence of reactions for energy production, which take place in the matrix of the mitochondria. The reaction cycle requires materials from the cytosol to be converted into acetyl CoA, which represents the starting point of a new cycle. Which of the following statements about acetyl CoA is TRUE:

a)Amino acids can be converted into acetyl CoA
b)Pyruvate is converted into acetyl CoA in the Cytosol
c)triacylglycerol molecules are transported into the mitochondrial matrix and cleaved by the kinases to produce acetyl CoA
d)Oxaloacetate is converted directly into acetyl CoA to fee the citric acid cycle

Answer 1

Acetyl CoA is produced during the conversion of pyruvate in the mitochondria and serves as the starting point of the citric acid cycle. The correct answer is b).

Step-by-step explanation:

Acetyl CoA is a molecule that is produced during the conversion of pyruvate in the mitochondria. It represents the starting point of the citric acid cycle. Therefore, option b) is the correct statement. Amino acids can indeed be converted into acetyl CoA, but this is not the main source of acetyl CoA for the citric acid cycle. Option c) is incorrect because triacylglycerol molecules are not directly converted into acetyl CoA, but rather broken down into fatty acids and then further metabolized. Finally, option d) is also incorrect because oxaloacetate is not directly converted into acetyl CoA but is instead combined with acetyl CoA to start a new cycle.