Question

Overall Glycolysis yields some ATPs, but in early stages, ATP is utilised to phosphorylate sugar substrates. In which of the following steps is ATP consumed?

• A. Sucrose to D-glucose catalysed by invertase
• B. Fructans to D-Fructose catalysed by β-fructofuranosidases
• C. Starch to glucose-1-phosphate catalysed by phosphorylase
• D. D-glucose to glucose-6-phosphate catalysed by hexokinase

Hint:

Remember that glycolysis involves two ATP-consuming steps: phosphorylation of glucose (hexokinase) and phosphorylation of fructose-6-phosphate (phosphofructokinase1).

Answer 1

The Correct Option is D

1. Glycolysis begins with hexokinase phosphorylating D-glucose into glucose-6-phosphate, consuming one ATP molecule.
2. This phosphorylation is crucial for trapping glucose within the cell and initiating glycolysis.
3. Alternative options include enzymatic cleavage or ATP-independent phosphorylation.