Splicing of mRNA occurs in spliceosomes and chemically is a

) Splicing of mRNA occurs in spliceosomes and chemically is a series of ________ reactions.

All processing of eukaryotic mRNAs takes place in the nucleus after transcription has been completed.(True/False)

Which of the following types of post-transcriptional processing does NOT occur for bacterial tRNAs?

A) Exonuclease cleavage

Degradation of bacterial mRNAs occurs:

A) from the 3\' end.

B) largely by the activity of non-specific nucleases.

C) from the 5\' end.

D) relatively slowly.

E) from both 3\' and 5\' ends at the same time.

B) Endonuclease cleavage

C) Non-template directed addition of bases

D) Methylation of bases

E) Addition of a phosphate group to the 5\' end

Solution

- Splicing of mRNA occurs in spliceosomes and chemically is a series of TRANSESTERIFICATION reactions.

- All processing of eukaryotic mRNAs takes place in the nucleus after transcription has been completed. ~ TRUE

Processing begins at the 5´ end, while the 3´ end is still being synthesized. Processing occurs in the nucleus and only mature RNA is transported out to the cytoplasm. Multiple RNA polymerases may transcribe the same template simultaneously.

- third question is not clear