Following statements are regarding to enzymatic processing of benzo(a)pyrene to a more potent mutagen and carcinogen.

A. Liver enzymes, particularly P-450 enzymes, modify benzo(a)pyrene in a series of reactions, producing 7,8-diol-9,10-epoxide, a highly potent mutagenic species that reacts with DNA primarily at the N2 atom of a guanine base.

B. The adduct, (+)-trans-anti-B(a)P-N2-dG, causes polymerase to insert an A rather than a C opposite the modified G base. Next time the DNA is replicated, a T will be inserted opposite the A, and the mutation will be complete.

C. Potent mutagen majorly causes conversion of guanine (G) to thymine (T) bases, a transition mutation.

D. When this potent mutagen applied to cultured bronchial epithelial cells, activated benzo(a)pyrene induces many mutations, including activating mutations at codons 175, 248, and 273 of the p53 gene.

Which of the following statements are correct?

#Question id: 5283

#Unit 8. Inheritance Biology

A generalized transducing phage is used to transduce an a- b- c- d- e- recipient strain of E. coli with an a+ b+c+d+ e+ donor. The recipient culture is plated on various media with the results shown in the table below What can you conclude about the linkage and order of the genes?

#Question id: 5282

#Unit 8. Inheritance Biology

Conjugation allowed between Hfr with genotype A B C D E and F- with genotype a b c d e. At regular intervals, a sample of cells was removed and agitated

vigorously in a kitchen blender to halt all conjugation and DNA transfer. After interrupted conjugation, ex-conjugate were selected on minimal media at regular interval and find different number of ex-conjugate?

abCde   - 10, abCdE    -    30 ,  aBCdE  -     40 , ABCdE  -     20 , ABCDE   -   50

What is gene order of those genes?

#Question id: 5281

#Unit 8. Inheritance Biology

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:

What is the order of transfer of the genes?

#Question id: 5280

#Unit 8. Inheritance Biology

In the mating Hfr met- his+ leu+ trp+ × F- met+ his- leu- trp-.  The met marker is known to be transferred very late. After a short time, the mating cells are interrupted and the cell suspensions plated on four different growth media. The amino acids in the growth media and the number of colonies observed on each are as follows:

histidine + tryptophan  250 colonies

histidine + leucine         50 colonies 

leucine + tryptophan    500 colonies

histidine                       10 colonies

What is the order of transfer of the genes

#Question id: 5279

#Unit 8. Inheritance Biology

In a transduction experiment, phage P1 is grown on a bacterial host of genotype A+ B+ C+ and the resulting lysate is used to infect a recipient strain of genotype A– B– C–. The genes are in an order such that B is in the middle, and the distance between A and B is greater than the distance between B and C. Based on this information, which of the following least genotype?

#Question id: 5278

#Unit 8. Inheritance Biology

What is the co-transduction frequency for the A and B genes, from the following dataset?(Assume that there has been selection for the A+ form of the A gene). Genotype                                Number

 A+B+C+                                   10

 A+B+C-                                    30

A+B-C+                                     20

 A+B-C-                                     40