So let's suppose the fatty acid makes its way into the cytoplasm of the target cell. What happens next? Well, the first thing that has to happen is a special type of enzyme found on the outer membrane of the mitochondria known as fatty acidicinase, or sometimes acyl coenzyme synthetase, has to actually activate the fatty acid. And it activates the fatty acid by ultimately creating a thio ester bond between the sulfur atom on the coenzyme molecule and the carbon atom on that fatty acid. So in a two step process, the enzyme fatty acid thy kinase catalyzed the formation of a thyroid bond between the carboxyl group of the fatty acid and the sulfur group of that coenzyme aid. So let's take a look at this two step process and let's begin with step one.