Multiple Choice
Which of the following is produced as a result of alternative splicing during RNA processing?
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10. Transcription
RNA Modification and Processing
Multiple Choice
In eukaryotes, which set of post-transcriptional processing steps typically modifies a newly synthesized pre-mRNA to produce a mature mRNA ready for export and translation?
A
Conversion of DNA to RNA by DNA polymerase, followed by replacement of uracil with thymine and addition of ribosomes to the 3′ end
B
Removal of exons by spliceosome-mediated splicing, addition of a 3′ 7-methylguanosine cap, and addition of a 5′ poly(A) tail
C
Addition of a 5′ 7-methylguanosine cap, removal of introns by spliceosome-mediated splicing, and addition of a 3′ poly(A) tail
D
Direct translation of the pre-mRNA into protein in the nucleus without capping, splicing, or polyadenylation
Verified step by step guidance1
Identify the key post-transcriptional modifications that occur in eukaryotic pre-mRNA to produce mature mRNA. These modifications prepare the mRNA for export from the nucleus and for translation in the cytoplasm.
Recall that the 5′ end of the pre-mRNA receives a special cap structure called the 7-methylguanosine cap. This cap protects the mRNA from degradation and assists in ribosome binding during translation.
Understand that introns (non-coding regions) are removed from the pre-mRNA by a complex called the spliceosome, which performs splicing to join the exons (coding regions) together.
Recognize that the 3′ end of the pre-mRNA is modified by the addition of a poly(A) tail, a stretch of adenine nucleotides, which enhances mRNA stability and aids in nuclear export.
Combine these steps to conclude that the typical post-transcriptional processing in eukaryotes includes: addition of a 5′ 7-methylguanosine cap, removal of introns by spliceosome-mediated splicing, and addition of a 3′ poly(A) tail.
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