You are studying four his- Salmonella strains (A, B, and C), each of which carries a different type of mutation in the same gene required for histidine biosynthesis. You treat bacteria from each strain with buffer only or buffer plus a base analog. You plate 108 bacteria from each treatment on medium that lacks histidine, allow colonies to grow.

+2 votes

 

You get the following results:

Strain A: The buffer only plate has 10 colonies; the buffer plus mutagen plate has 10 colonies.

Strain B: The buffer only plate has 10 colonies; the buffer plus mutagen plate has 100 colonies.

Strain C: The buffer only plate has 100 colonies; buffer plus mutagen has 100 colonies.

Use this information to answer the following questions.

 

Part A

 

 

 

 

Part B

Which of the following is a possible description of the his- mutation that is in Salmonella strain B? Select all that apply.

 

Part C

Which of the following is the best explanation for the results obtained with Salmonella strain C?

 

Part D

Which of the following statements is a reasonable explanation for the phenotype of Strain C (see answer to part C)?

 

 

asked Nov 22, 2012 in Genetics by GeneX ~Top Expert~ (7,947 points)
    

1 Answer

+1 vote

Part A:

Frameshift mutation, Deletion mutation, Transversion mutation

 

Part B:

Transition mutation

 

Part C:

Strain C has a high spontaneous mutation rate

 

Part D:

 

 

answered Nov 22, 2012 by GeneX ~Top Expert~ (7,947 points)

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