Pentose phosphate pathway: the nonoxidative phase
A rapidly dividing cell needs large amounts of ribose-5-phosphate for nucleotide synthesis but little NADPH. How can it meet this need?
Answer A: explanation for every choice
A
Correct. Transketolase and transaldolase can convert fructose-6-phosphate and glyceraldehyde-3-phosphate into ribose-5-phosphate without making NADPH.
B
The oxidative phase makes NADPH along with ribose-5-phosphate, which this cell doesn't need.
C
Gluconeogenesis makes glucose, not ribose.
D
β-oxidation produces acetyl-CoA, not sugars.
TakeawayOxidative phase: NADPH plus pentoses. Nonoxidative phase: reversible sugar interconversion.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb112.