Question

Which of the following lists steps of mRNA production in eukaryotes in the correct order?A) 5' cap addition, addition of poly-A tail, exon splicing, passage through nuclear membrane, transcriptionB) Transcription, 5' cap addition, addition of poly-A tail, exon splicing, passage through nuclear membraneC) Transcription, 5' cap addition, addition of poly-A tail, passage through nuclear membrane, exon splicingD) Transcription, addition of poly-A tail, 5' cap addition, exon splicing, passage through nuclear membrane

Answer 1

Answer:

The correct answer is B) Transcription, 5' cap addition, addition of poly-A tail, exon splicing, passage through nuclear membrane.

Explanation:

The transcription process in eukaryotes takes place in the nucleus of the cell and after transcription post-transcriptional modification also takes place in the nucleus which is necessary to guide the mRNA out of the nucleus.

First, the process of transcription takes place in which DNA is transcribed to mRNA by an enzyme called RNA polymerase. After transcription post-transcriptional modifications takes place in the given order.

1. Capping: In capping process 7-methylguanosine is added by capping enzyme at 5' end of mRNA.

2. Polyadenylation: In polyadenylation, many poly-A residues are added at the 3' end of the mRNA called the poly-A tail.

3. Intron splicing: Introns are the non-coding sequence present in mRNA which are spliced out of mRNA and all exons are joined together.

After these post-transcriptional process, the mature mRNA is transported out of the nucleus through the nuclear membrane.