Explanation

Triose phosphate isomerase enzyme converts glyceraldehydes-3 phase molecule into dihydroxy acetone phosphate. Then an enzyme transketolase comes, which acts on sedoheptulose-7-phosphate molecule and changes it into ribulose-5-phosphate and xylulose-5-phosphate. Then ribulose-5-phosphate isomerase enzyme comes and acts on ribulose-5-phosphate. This reactionhas a molecule of ribulose-5-phosphate, while xylulose-5-phosphate molecule is also converted into ribulose-5-phosphate by ab other enzyme, ribulose-5-phosphate epimerase.