Question

In 1906 Harden and Young, in a series of classic studies on the fermentation of glucose to ethanol and CO2 by extracts of brewer's yeast, made the following observations.(A) Inorganic phosphate was essential to fermentation; when the supply of phosphate was exhausted, fermentation ceased before all the glucose was used.(B) During fermentation under these conditions, ethanol, CO2, and a sugar phosphate accumulated.(C) When arsenate was substituted for phosphate, no sugar phosphate acumulated, but the fermentation proceeded until all the glucose was converted to ethanol and CO2.Answer the following questions.1. Which enzyme of glycolysis requires inorganic phosphate and therefore stops when no phosphate is available?(a) glyceraldehyde 3-phosphate dehydrogenase(b) phosphoglycerate mutase(c) phosphofructokinase-1(d) phosphoglycerate kinase

Answer 1

Answer:

(a) glyceraldehyde 3-phosphate dehydrogenase.

Explanation:

Glyceraldehyde 3-phosphate dehydrogenase is the enzyme which requires inorganic phosphate (Pi) essentially for it's functioning. It catalyzes the conversion of glyceraldehyde 3-phosphate into 1,3-bisphosphoglyceric acid (1,3 BPG) during glycolysis.

All other enzymes of glycolysis use ATP for phosphorylation of their substrate but this is the only enzyme which rather uses an inorganic phosphate to phosphorylate it's substrate.