Question

In glycolysis, a glucose-phosphate is transformed into a fructose-phosphate. Which of the following reasons provides the best chemical rationale for this transformation? Choose the best answer.

	A.	It is not possible to break a molecule of glucose into two pieces but it is possible to break a molecule of fructose into two pieces.
	B.	Glucose is not a high phosphotransfer potential molecule but fructose is a high phosphotransfer potential molecule.
	C.	There are no enzymes to add phosphate groups to glucose but there are enzymes to add phosphate groups to fructose.
	D.	If glucose were broken into two pieces the molecules would have unequal length but if fructose is broken into two pieces the molecules will have the same length.

Answer 1

Option a cannot be considered because the breaking down of glucose and fructose into smaller molecules in glycolysis occurs and this is through a series of reactions.Although this statement explains the concept it cannot be considered a precise reason.

Option b is correct because in glucose we have an aldehyde group and in fructose keto group is presence.It is easier to phosphorylate the fructose into biphosphate to yield the interconvertable products due to its high phosphotransfer potential.This process is difficult with glucose because due to low phosphotransfer potential of glucose this process is difficult.

Option c is incorrect because is often phoporylated in the body.

Option d is incorrect because both glucose and fructose are hexose sugars,ie; both of them contain 6 carbons each and if broken down both the molecules will result in equal length products.

Therefore option b is the right answer.