Four mutant lines of yeast are unable to produce the amino a

Four mutant lines of yeast are unable to produce the amino acid Proline. In each of the four mutant lines, a different compound accumulates: compound A in mutant line 1, compound B in mutant line 2, compound C in mutant line 3, and compound D in mutant line 4. Each mutant strain is cultured in the presence of various media, and the mutants that grow in a specific medium are denoted by a +, while those that fail to grow are denoted by a Based on these data, depict the correct order of intermediate compounds (A, B, C, D) in the proline biosynthetic pathway and point out the correct point at which each mutant gene (1, 2, 3, 4) acts in the pathway.

Solution

Compound D: 1-pyrroline-5-carbohydrate (every mutant grows in the presence of D except mutant 1 that is why mutanat 1 is defecient in Pyrroline-5-caboxy reductase enzyme)

compound C: L-Glutamate (any mutant does not grow in the presence of compound C because it is L-glumate and it is the first component of proline biosynthesis and if the mutantions are there in any of the gene involve in the biosyntheis, they will not allow the biosyntheis even L-glutamate is present and mutant 3 is defecient in the enzyme glutamate 5-kinase because its not able to convert L glutame to its product and that is why growth is stoped)

Compound B: L-Glutamate 5-semiadehyde (Mutant 2 is defecient in glutamate 5 semialdehyde)

compound A: L- glutam-5-yl Phosphate (Mutant 4 is also defecient in glutamate 5 semialdehyde