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?

TLS Online TPP Program

#Question id: 24490

#Unit 3. Fundamental Processes

There are three type of Splicing signals 1. Major U2-type or GU-AG introns 2. Minor U12-type or AU-AC introns & 3. Minor U12-type with GU-AG introns (hybrid type), which of the following is responsible for the recognition of branch point sequence UACUAAC?

TLS Online TPP Program

#Question id: 24489

#Unit 3. Fundamental Processes

Two transesterification reactions takes place for 2 exon -1 intron configuration. Choose the correct  statement 

a. First transesterification is always caused by exon 1 -3’OH

b. second transesterification is catalysed variably either by external G or branch point while .

c. First transesterification is catalysed variably either by external G or branch point while 

d. second transesterification is always caused by exon 1 -3’OH.

TLS Online TPP Program

#Question id: 24464

#Unit 3. Fundamental Processes

rRNA are encoded by two type of RNA pol. RNA pol I and RNA pol III in which 5.8s rRNA is encodes by …………. While 5s rRNA encoded by ……

TLS Online TPP Program

#Question id: 4350

#Unit 3. Fundamental Processes

Portions of the DNA sequences of normal and mutant b-globin genes are shown. The most plausible explanation for why the indicated mutation (changing an A to a G) results in the disease b-thalassemia is that the mutation

TLS Online TPP Program

#Question id: 4349

#Unit 3. Fundamental Processes

RNA Pol IV and Pol V

TLS Online TPP Program

#Question id: 4122

#Unit 3. Fundamental Processes

RNA Pol uses its active site, in a simple back-reaction, to catalyze the removal of an incorrectly inserted ribonucleotide. This phenomenon known as