which step in glycolysis involves the process where direct substrate phosphorylation occurs? (a) 3- phosphoglycerate to phosphoenolpyruvate (b) 1,3, bisphosphoglycerate to 3-phosphoglycerate and phosphoenolpyruvate to pyruvate (c) fructose-6-phosphate to fructose1,6-bisphosphate (d) 3- phosphoglycerate to 2-phosphoglycerate and phosphoenolpyruvate to pyruvate
