Question

Suppose you discovered a mutant yeast whose glycolytic pathway was shorter because of the presence of a new enzyme catalyzing the following reaction Glyceraldehyde 3-phosphate + H2O + NAD+ → NADH + H+ + 3-phosphoglycerate Which of the following changes would you expect to find in the growth and metabolism of the mutant yeast?
The formation of pyruvate from glucose will be energetically more favorable
The mutation will cause the yeast to grow faster under anaerobic conditions.
The mutant will not grow under anaerobic conditions
The mutant will not grow under aerobic conditions.
The formation of pyruvate from glucose will be energetically less favorable.
The mutation will cause the yeast to grow faster under aerobic conditions

Answer 1

Answer:

The correct answer is  the formation of pyruvate from glucose willl be energetically less favorable.

Explanation:

According to the question matunt yeast has a shorter glycolytic pathay catalysing a follwing reaction

 Glyceraldehyde-3-phosphate+H2O+NAD+  = 3-phosphoglycerate

So in the mutatant the formation of 1,3- bisphosphoglycerate is not occurring.The glyceraldehyde-3-phosphate is directly converted into 3-phosphoglycerate.

    As a result the substrate level phosphorylation step that deals with formation of 3-phosphoglycerate from 1,3  bisphosphoglycerate is not occurring.

  From this point of view it can be said that less energy will be formed in the mutant during glycolysis than that of normal one.

 So the formation of pyruvate from glucose will be energetically less favorable.