Citrate can be used as an energy source by yeast How is citr

Citrate can be used as an energy source by yeast. How is citrate used?

A.It undergoes glycolysis.

B.It is an intermediate of the Kreb\'s cycle.

C.It is a protein of the electron transport chain.

D.When glycogen is degraded, it produces citrate.

Solution

Choice B

Explanation: Citrate is a 6 carbon compound which is generated from dehydration reaction of oxaloacetate in the Kreb\'s cycle. As soon as citrate is generated, it is converted into isocitrate by the enzyme cis-acotinase. It must be closely observed here that citrate is an important intermediate of the Kreb\'s cycle. In the absence of citrate, the forward progression of Kreb\'s cycle will not take place and hence the cylce will not proceed. Moreover, excess of citrate generation is also a switch for compelling the Kreb\'s cycle to decrease its pace for some time and let the homeostasis be maintained so that a metabolic balance might be maintained in the cell. Thus, being an integral, rate limiting and crucial factor of Kreb\'s cycle, supply of citrate can directly lead to onset of metabolic pathways in yeast and higher eukaryotes.