In glycolysis, the aldolase reaction cleaves fructose-1,6-bisphosphate. What are the two triose-phosphate products generated by this split?

Introduction / Context:In the payoff phase of glycolysis, the six-carbon sugar fructose-1,6-bisphosphate (F1,6BP) is split by aldolase into two three-carbon intermediates. Correctly naming these products is foundational for understanding how glycolysis doubles the number of triose substrates feeding subsequent ATP-generating steps.

Given Data / Assumptions:

• Substrate: F1,6BP.
• Enzyme: aldolase (class I in animals).
• Products are triose phosphates that rapidly interconvert.

Concept / Approach:Aldolase catalyzes a reversible aldol cleavage producing dihydroxyacetone phosphate (DHAP, a ketotriose phosphate) and glyceraldehyde-3-phosphate (GAP, an aldotriose phosphate). Triose phosphate isomerase then interconverts DHAP and GAP, funneling both carbons through GAP for oxidation and ATP generation.

Step-by-Step Solution:

Verification / Alternative check:Isotopic labeling experiments show distribution of carbon atoms into GAP and DHAP consistent with the aldolase mechanism.

Why Other Options Are Wrong:

• GAP only or DHAP only: aldolase yields both simultaneously.
• Fructose-6-phosphate + GAP: F6P is upstream, not an aldolase product.
• None of the above: a standard product pair exists.

Common Pitfalls:Confusing aldolase products with phosphofructokinase substrates, or forgetting the rapid isomerization that equalizes triose pools.

Final Answer:Glyceraldehyde-3-phosphate and dihydroxyacetone phosphate