#Question id: 5281
#XL - S Microbiology
In the mating Hfr Strs met+ his+ leu+ trp+ Ala+ X F- Strres met- his- leu- trp- Ala-. At regular interval time, the mating cells are interrupted and the cell suspensions plated on four different growth media with streptomycin. The amino acids in the growth media and the number of colonies observed on each are as follows:
|
Interrupted time |
Composition of media |
Growth |
||||
|
His |
Leu |
Ala |
Trp |
Met |
||
|
2 min |
+ |
- |
+ |
+ |
+ |
Yes |
|
10 min |
+ |
- |
- |
+ |
+ |
Yes |
|
12 min |
+ |
- |
- |
+ |
- |
No |
|
15 min |
+ |
- |
- |
- |
+ |
Yes |
|
20 min |
- |
- |
- |
- |
+ |
Yes |
What is the order of transfer of the genes?
#Question id: 5285
#XL - S Microbiology
A transformation experiment is carried out using donor DNA that is A+B+C+ and a recipient that is A-B- C-. A+ transformants are selected and tested further. Of these, 64% are B+ and none are C+. Also, B+ are selected, and 8% are also C+. What is the gene order
#Question id: 5287
#XL - S Microbiology
Interrupted matting of different Hfr strain with F- E.coli cell resulting generation of following strain Order of gene is
#Question id: 5290
#XL - S Microbiology
The following table shows mapping data from three interrupted mating experiments using three different Hfr strains and an F- strain: The order of genes is
#Question id: 5295
#XL - S Microbiology
A cross is made between an Hfr that is met+ thi+ pur+ and an F-that is met- thi- pur-. Interrupted mating studies show that met+ enters the recipient last, so met+ recombinants are selected on a medium containing supplements that satisfy only the pur and thi requirements. These recombinants are tested for the presence of the thi+ and pur+ alleles. The following numbers of individuals are found for each genotype:
|
A) Gene Order |
I |
Thi Pur Met |
|
II |
Pur Met Thi |
|
|
III |
Pur Thi Met |
|
|
B) Distance between Pur and Thi |
IV |
15.4 map unit |
|
V |
1.8 map unit |
What is the following correct combination?
#Question id: 5298
#XL - S Microbiology
Four E. coli strains of genotype a+ b− are labeled 1, 2, 3, and 4. Four strains of genotype a− b+ are labeled 5, 6, 7, and 8. The two genotypes are mixed in all possible combinations and (after incubation) are plated to determine the frequency of a+ b+ recombinants. The following results are obtained, where M = many recombinants, L = low numbers of recombinants, and 0 = no recombinants. On the basis of these results, assign a sex type (either Hfr, F+, or F−) to each strain