Multiple Choice
Which of the following does NOT increase the stability of eukaryotic mRNAs?
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15. Gene Expression
Eukaryotic RNA Processing and Splicing
Multiple Choice
How do small nuclear RNAs (snRNAs) in the spliceosome initiate the splicing of pre-mRNA?
A
They base-pair with specific sequences at the intron-exon boundaries to guide the spliceosome to the correct splice sites.
B
They transport the pre-mRNA out of the nucleus after splicing.
C
They degrade introns by acting as ribonucleases.
D
They directly catalyze the addition of a 5' cap to the pre-mRNA.
Verified step by step guidance1
Understand the role of small nuclear RNAs (snRNAs) in the spliceosome. These are RNA molecules that are part of the spliceosome complex, which is responsible for removing introns from pre-mRNA during RNA processing.
Recognize that snRNAs function by base-pairing with specific sequences at the intron-exon boundaries. This helps the spliceosome identify the correct splice sites on the pre-mRNA.
Learn that the spliceosome uses snRNAs to guide the splicing process. The snRNAs help align the pre-mRNA in a way that allows the spliceosome to catalyze the removal of introns and the joining of exons.
Clarify that snRNAs do not transport pre-mRNA out of the nucleus, degrade introns as ribonucleases, or catalyze the addition of a 5' cap. These are separate processes unrelated to the splicing function of snRNAs.
Conclude that the correct mechanism involves snRNAs base-pairing with intron-exon boundary sequences to guide the spliceosome to the correct splice sites, ensuring accurate splicing of pre-mRNA.
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