LABORATORY REVIEW
MOLECULAR BIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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cutting introns out and spicing exons together
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adding the 5’ cap
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adding the 3’ poly A tail
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all of these are correct
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Detailed explanation-1: -Overview of pre-mRNA processing in eukaryotes In the nucleus, a pre-mRNA is produced through transcription of a region of DNA from a linear chromosome. This transcript must undergo processing (splicing and addition of 5’ cap and poly-A tail) while it is still in the nucleus in order to become a mature mRNA.
Detailed explanation-2: -Eukaryotic transcripts possess extra segments called introns or intervening sequences or noncoding sequences. They do not appear in mature or processed RNA. The functional coding sequences are called exons. Splicing is removal of introns and fusion of exons to form functional RNAs.
Detailed explanation-3: -In eukaryotic cells, before RNA polymerase II-generated transcripts could be translated into protein products, these transcripts (pre-mRNAs) need to be suitably processed to form messenger RNA (mRNA). Three major events constitute pre-mRNA processing: (a) 5′-end capping, (b) splicing, and (c) 3′-end polyadenylation.
Detailed explanation-4: -In eukaryotes, transcription produces a pre-mRNA molecule that be processed into mature mRNA by the addition of a 5′ cap, a 3′ poly-A tail, and through RNA splicing. At the end of eukaryotic transcription, a pre-mRNA molecule is formed.