The intermediate products of glycolysis include glucose-6-phosphate, fructose-6-phosphate, fructose-1 6-bisphosphate, PGAL, bisphosphoglycerate, and PEP. The main intermediate products are fructose-1 6-bisphosphate, PGAL, and PEP.

Phosphofructokinase-2 converts fructose-6-phosphate to fructose-2,6-bisphosphate.

Phosphofructokinase-1 (PFK-1)

Fructose 1, 6-bisphosphate to dihydroxyacetone phosphate (DHAP) and Glyceraldehyde-3-Phosphate. Aldolase

Yes, the early stages of glycolysis involve phosphorylation.

glucose + P -> glucose-6-phosphate -> (fructose-6-phosphate = an isomer) -> fructose -1,6 - bisphosphate.

Therefore, in the first 4 steps, the starting substance glucose is phosphorylated twice to give fructose -1,6- bisphosphate, which can be split into two triose phosphates.