Question

Triose phosphate isomerase interconverts dihydroxyacetone phosphate and glyceraldehyde-3-phosphate. Mutants of yeast or bacteria that lack triose phosphate isomerase are viable under aerobic conditions but cannot grow in the absence of oxygen. Explain (a) why these mutants cannot grow anaerobically and (b) why they can grow aerobically.

Answer 1

Answer:

Explained

Explanation:

Due to lack of of Triose phosphate isomerase cell will be unable to interconvert Dihydroxyacetone to glyceraldehyde 3 phosphate.

And the cells will be able to complete the glycolysis only in the presence of glyceraldehyde 3 phosphate which will generate 2 ATP and hence the net ATP gain during whole process in anaerobic condition will be Zero. This will lead to the dath of the mutant yeast.

a) While in case of aerobic condition, only one molecule of pyruvate will also be able to produce more ATP compared to anaerobic condition by further oxidation which is sufficient for yeast to survive.

b)  the cells will be able to complete the glycolysis only in the presence of glyceraldehyde 3 phosphate which will generate 2 ATP and hence the net ATP gain during whole process in anaerobic condition will be Zero. This will lead to the death of the mutant yeast.