GlycolysisEdexcel A-Level Biology B: Mind map

Exam questions on Glycolysis

1. A biochemist adds glucose to an extract of yeast cytoplasm that contains all the enzymes of glycolysis, together with NAD, ADP and phosphate, but no ATP. No reaction takes place. When a small amount of ATP is added, glycolysis begins and pyruvate is soon detected.
   Explain why glycolysis does not begin in this extract unless ATP is added.2 marks
2. A student supplies a cytoplasm extract with 2.0 mmol of glucose, with excess ATP, ADP, NAD and phosphate. After incubation she finds that all of the glucose has been converted to pyruvate.
   Calculate the net amount of ATP gained by the extract. Show your working.2 marks
3. A researcher adds an inhibitor to a yeast cytoplasm extract. The inhibitor blocks the enzyme that converts glycerate 3-phosphate (GP) to pyruvate. She supplies glucose and a limited amount of ATP, and measures the concentrations of ATP, GP and pyruvate every minute for 10 minutes.
   Explain why the concentration of ATP in the inhibited extract falls and stays low.3 marks