After an mRNA strand has been transcribed from DNA, it must be processed before translation can take place.

Question

After an mRNA strand has been transcribed from DNA, it must be processed before translation can take place. Which of the following statements are true about the RNA editing process? More than one answer
Additional amino acids are added before translation occurs.
A cap is added to one end of the mRNA molecule.
Editing occurs in the cytosol as the new mRNA strand leaves the nucleus.
Noncoding segments are removed and exons are joined together.

Answer 1

Hi Susan,

 

Translation itself is the systematic addition of amino-acids that are encoded by mRNA.

 

Transcription and translation follow different sequence of events in prokaryotes and eukaryotes. In other words, mechanisms are different in eukaryotes and prokaryotes.

 

In eukaryotes, pre-mRNA is transcribed in nucleus, it is then processed to mature mRNA in cytoplasm by addition of a cap at 5' end, splicing through out the length of the transcript and then Polyadenylation at 3' end to stabilize the mature transcripts.

 

There are mutants where pre-mRNA fails to be transported to cytoplasm and therefore, mature transcript is missing. If a molecule or two are transported then it is not adequate to make detectable protein.

 

Failure of Polyadenylation or improper Polyadenylation  leads to highly unstable transcript that can be detected but does not make adequate protein since mRNA is destroyed before translation.

 

RNA processing is primarily a phenomenon in eukaryotes that has specific steps prior to translation.

 

Hope this helps as well.

Answer 2

 

A cap is added to one end of the mRNA molecule.

Noncoding segments are removed and exons are joined together.