So what happens in step number one in this reaction? So in step number one, we have the hydrolysis of ATP by this carboxylase and the energy that is released in the hydrolysis of ATP helps us attach a carbon dioxide onto the biotin. So in step number one we form, and that's not shown aboard, but we form a complex that consists of carbon dioxide attached onto biotin, which is also attached onto the carboxylase. Now, in the second step that once again is not shown, that carbon dioxide is transferred from the biotin onto the Cecil coenzyme A molecule and we generate malanyl coenzyme A. So that's the importance of biotin. Biotin allows the binding of that carbon dioxide which ultimately transfers that carbon dioxide onto the CEO coenzyme A to form this Malnol coenzyme A.