Which of the following best explains why an enzyme hasn't evolved to catalyze the following reaction as the first step of glycolysis? glucose + pi glucose-6-phosphate i. the use of atp is required for this step to serve as a regulatory control point. ii. the use of atp is important because it keep its concentration low. otherwise the high [atp] would slow glycolysis too much through feedback inhibition. iii. the large positive of this reaction would need to be overcome by an exceedingly high [pi]. iv. inorganic phosphate cannot be specifically placed on the carbon in the 6th position.