In which reactions of glycolysis are isomerase enzymes involved?
A) To convert fructose 1-6-diphosphate to glyceraldehyde 3-phosphate and dihydroxy-acetone phosphate.
B) When four enzyme-catalysed reactions convert each triose phosphate molecule to a molecule of pyruvate.
C) When glucose-6-phosphate is changed to fructose-6-phosphate.
D) In the steps in which dehydrogenase enzymes are involved.
E) During the phosphorylation of both glucose and fructose-1-phosphate.
IMAT 2023 · Question 29
Q29 - Glycolysis
Pinned
The correct answer is C) When glucose-6-phosphate is changed to fructose-6-phosphate.
An isomerase turns a molecule into an isomer, keeping the same formula with a different structure. In glycolysis that happens at glucose-6-phosphate → fructose-6-phosphate, catalysed by phosphoglucose isomerase.
A is the step right next to it and catches people: splitting fructose-1,6-bisphosphate into two trioses is done by aldolase, not an isomerase. Phosphorylations (E) are kinases.
(There's a second isomerase in glycolysis, triose phosphate isomerase, but it isn't one of the options.)
Replies 0
No other replies yet.
Log in to reply.