Final answer:
Beta-oxidation of fatty acids is a process that occurs primarily in the mitochondria and involves converting fatty acids into acetyl-CoA, which then enters the Krebs cycle for ATP production.
Step-by-step explanation:
Beta-Oxidation of Fatty Acids
The breakdown of fatty acids, a process known as beta-oxidation, involves several steps that occur primarily within the mitochondria of cells. Short and medium-chain fatty acids undergo beta-oxidation after they are transported into the mitochondria. Initially, in the cytoplasm, fatty acids are activated to form fatty acyl CoA molecules. These molecules combine with carnitine to create fatty acyl carnitine, which aids in transporting the fatty acid across the mitochondrial membrane. Inside the mitochondrial matrix, fatty acids are further processed.
Oxidation Process Inside the Mitochondria
Once the fatty acyl carnitine enters the mitochondrial matrix, it is reconverted into fatty acyl CoA. This molecule undergoes a four-step cycle that sequentially removes two carbon atoms at a time from the fatty acid chain, eventually forming acetyl-CoA. The acetyl-CoA then enters the Krebs cycle and participates in the energy production in the form of ATP, similar to acetyl CoA derived from pyruvate.
Fatty acids with odd numbers of carbons are metabolized somewhat differently, with the last beta-oxidation cycle yielding both acetyl-CoA and propionyl-CoA. This propionyl-CoA is further oxidized into succinyl-CoA, which then enters the Krebs cycle. The process for unsaturated fatty acids also includes additional steps to manage the double bonds.