So we have to have an acetyl glutamate to actually activate the carbon well phosphate synthetase to allow it to undergo these reactions and produce carbon well phosphate. And because this enzyme lies in the matrix of the mitochondria, this step takes place in the matrix of the mitochondria. Now step two also takes place in the matrix of the mitochondria because the enzyme ornithine transcarbomolase lies in the matrix of the mitochondria. And so what this enzyme does is it takes this product of reaction one and it transfers this carbon group kicking off the orthophosphate, it transfers this group onto ornathine to form citrulline. So this is what ornithine looks like. And ultimately this group here, minus this oxygen and this phosphate group is transported onto this nitrogen of the ornathine to form the citrulline.