If we were to sum the concentration of each intermediate in the tca cycle, we could find the total concentration of carbon backbones in the tca cycle. some metabolic pathways lower the concentration of carbon backbones in the tca cycle since these reactions consume molecules like α-ketoglutarate and oxaloacetate, which are intermediates in the tca cycle. other metabolic pathways increase the concentration of tca cycle carbon backbones, since tca cycle intermediates are end products of those pathways. for each of the following reactions, would the concentration of carbon backbones in the tca cycle increase, decrease, or remain the same? label each reaction with its effect on the overall concentration of tca cycle intermediates.