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.
B) Triacylglycerol molecules are transported into the mitochondrial matrix and cleaved by kinases to produce acetyl CoA.
D) Oxaloacetate is converted directly into acetyl CoA to feed the citric acid cycle.

Answer 1

The correct statement about acetyl CoA in relation to the citric acid cycle is that amino acids can be converted into acetyl CoA.

Step-by-step explanation:

The correct statement about acetyl CoA with respect to the citric acid cycle is A) Amino acids can be converted into acetyl CoA. The conversion of pyruvate to acetyl CoA does not occur in the cytosol but in the matrix of the mitochondria, making the statement B) incorrect.

Statement B) is also incorrect, as triacylglycerol molecules are first broken down into fatty acids and glycerol in the cytosol, and fatty acids then enter the mitochondria where they undergo β-oxidation to form acetyl CoA, not cleaved by kinases. Finally, statement D) is incorrect because oxaloacetate is a molecule that is regenerated at the end of the citric acid cycle; it does not convert directly into acetyl CoA but instead combines with it to start the cycle.