Question

Q. During glycolysis, the direct conversion of fructose-6-phosphate from glucose can be done, but first of all the glucose is converted into glucose-6-phosphate and then to fructose-6-phosphate..

Why ?

Answer 1

The first step in glycolysis is catalyzed by hexokinase, an enzyme with broad specificity that catalyzes the phosphorylation of six-carbon sugars. Hexokinase phosphorylates glucose using ATP as the source of the phosphate, producing glucose-6-phosphate, a more reactive form of glucose. This reaction prevents the phosphorylated glucose molecule from continuing to interact with the GLUT (glucose transporter) proteins. It can no longer leave the cell because the negatively-charged phosphate will not allow it to cross the hydrophobic interior of the plasma membrane.