Q 21 :    

Which of the following are the post-transcriptional events in an eukaryotic cell?                   [2025]

A. Transport of pre-mRNA to cytoplasm prior to splicing.

B. Removal of introns and joining of exons.

C. Addition of methyl group at 5’ end of hnRNA.

D. Addition of adenine residues at 3' end of hnRNA.

E. Base pairing of two complementary RNAs.

Choose the correct answer from the options given below :

  • A, B, C only

     

  • B, C, D only

     

  • B, C, E only

     

  • C, D, E only

     

(2)

The process of copying genetic information from one strand of the DNA into RNA is known as transcription. It occurs in the cytoplasm with the help of transcripting enzyme.

Transport of pre-mRNA to cytoplasm prior to splicing is a part of transcription.

The primary transcript is converted into functional mRNA after post transcriptional processing involves 3 steps as follows-

•   Modification of 5’ end by capping,

•   Tailing,

•   Splicing.

Base pairing of two complementary RNA is not on event of post-transcription. Hence, statements B, C, D are post-transcriptional modification events in eukaryotic cell.

 



Q 22 :    

Which factor is important for termination of transcription?                     [2025]

  • α (alpha)

     

  • σ (sigma)

     

  • ρ (rho)

     

  • γ (gamma)

     

(3)

In prokaryotes the RNA polymerase is only capable of catalysing the process of elongation. It associates transiently with initiation factor (σ) and termination factor (ρ) to initiate and terminate the transcription respectively.