Optometry Admission Test (OAT) Practice

What role does beta oxidation play in the liver during homeostasis?

1. It generates glucose from proteins

2. It converts fatty acids into ketones

3. It synthesizes bile acids

4. It processes amino acids into ammonia

The correct answer is: It converts fatty acids into ketones

Beta oxidation is a crucial metabolic process that occurs in the mitochondria of liver cells, where fatty acids are broken down into acetyl-CoA units. This process becomes particularly important during states of fasting or prolonged exercise when glucose availability is low. During these conditions, the liver increases its reliance on fatty acids as an energy source. As fatty acids are oxidized through beta oxidation, the acetyl-CoA produced can enter the citric acid cycle for energy production or, in situations where glucose is scarce, can be converted into ketone bodies. These ketones (such as acetoacetate and beta-hydroxybutyrate) are then released into the bloodstream and can be utilized by other tissues, including the brain, as an alternative energy source. This adaptation helps maintain energy homeostasis when glucose levels are limited. The other choices relate to different metabolic processes. While glucose can be generated from proteins through gluconeogenesis, this is not the primary role of beta oxidation. Bile acid synthesis and the processing of amino acids into ammonia are also separate metabolic pathways that do not involve the breakdown of fatty acids. Hence, the generation of ketones from fatty acids through beta oxidation is specifically tied to the liver's role in energy metabolism during homeostasis