AFAA Personal Trainer Certification Practice Exam

What process breaks down fatty acids into two-carbon fragments for energy production?

1. Krebs cycle

2. Beta oxidation

3. Glycolysis

4. Electron transport system

The correct answer is: Beta oxidation

Beta oxidation is the process that specifically breaks down fatty acids into two-carbon fragments, known as acetyl-CoA, for energy production. This metabolic pathway takes place in the mitochondria of cells and is essential for utilizing fats as an energy source. Once the fatty acids are transported into the mitochondria, enzymes facilitate the sequential removal of two carbon units from the fatty acid chain. These two-carbon fragments can then enter the Krebs cycle, where they are further oxidized to produce ATP, the energy currency of the cell. In contrast, the Krebs cycle is responsible for further aerobic respiration after beta oxidation but does not directly break down fatty acids itself. Glycolysis is a pathway for breaking down glucose, primarily, and does not involve fatty acids directly. The electron transport system is the final stage of cellular respiration where ATP is generated through the oxidation of NADH and FADH2 produced in previous steps, but it does not initiate the breakdown of fatty acids.