. Auxotrophic strains A-D are compared with a wild type strain that can synthesi
ID: 94372 • Letter: #
Question
. Auxotrophic strains A-D are compared with a wild type strain that can synthesize a nutrient required for growth. In the wild type strain there is a single starting compound, followed by three intermediate compounds, before the final nutrient is produced. All mutant strains have a block somewhere I the pathway, but because they have different blocks, they are able to survive if different intermediate compounds are provided. A “+” means growth if the given compound (1-5) is provided and “-“ means no growth.
Strain
1
2
3
4
5
A
-
+
-
-
-
B
-
+
-
-
+
C
+
+
-
-
+
D
+
+
-
+
+
Wild type
+
+
+
+
+
Determine the order of the intermediates and also indicate where, in the pathway, each strain A-D is blocked. 2 pts
Strain
1
2
3
4
5
A
-
+
-
-
-
B
-
+
-
-
+
C
+
+
-
-
+
D
+
+
-
+
+
Wild type
+
+
+
+
+
Explanation / Answer
Answer:
Order of intermediate: 3 - 4 - 1 - 5 - 2
Explanation: Inclusion of last product in the pathway (nutrient 2) leads to growth in all the strains, This implies that 2 is important for the growth and survival of all strains and therefore will be the final product.
Similarly, addition of intermediate #3 causes no growth for any strain. It must be first compound in the pathway as the strains are missing or are blocked for conversion of this compound to final product.
Order of all other intermediates, can be analyzed in the same way.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.