alleryStart learning →Which enzyme adds the second phosphate during glycolysis and acts as a rate-limiting enzyme for the pathway?
APyruvate dehydrogenase
BPhosphofructokinase
CPhosphoglycerate kinase
DLactate dehydrogenase
Answer & Solution
Correct answer: B. Phosphofructokinase
1. The third step phosphorylates fructose-6-phosphate and is catalysed by phosphofructokinase.
2. A second adenosine triphosphate molecule donates the phosphate, giving fructose-1,6-bisphosphate.
3. Phosphofructokinase is a rate-limiting enzyme in this pathway.
4. Aldolase acts one step later and cleaves the sugar rather than phosphorylating it.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 7 "Cellular Respiration", section 7.2 Glycolysis_
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