Which of the following is NOT a type of ketone body?

Ketone bodies are produced during the metabolism of fatty acids and are primarily used as an energy source when glucose is scarce. The three main types of ketone bodies are acetoacetic acid, beta-hydroxybutyric acid, and acetone.

Acetoacetic acid is a ketone body that can be converted into other forms of energy. Beta-hydroxybutyric acid, while technically not a true ketone as it lacks a ketone group, is still classified as a ketone body due to its role in metabolism and its derivation from acetoacetate. Acetone is another type of ketone body, known for its volatility and role in exhalation as well as being a byproduct of ketone metabolism.

Acetyl-CoA, on the other hand, is not a ketone body. It is a crucial intermediary compound in various metabolic pathways, including the citric acid cycle and fatty acid synthesis but it is not classified as a ketone body. Its precursor role and involvement in metabolic processes distinguish it from the three primary ketone bodies.