22 Questions
Which proteins are part of the spliceosome complex?
Prp3, Prp6, Prp9
What is responsible for removing introns from pre-mRNA?
Spliceosome
Which components make up a spliceosome?
snRNPs and snRNAs
What is the main function of snRNPs in splicing?
Removing introns from pre-mRNA
How does the composition of the spliceosome change during splicing?
New snRNPs are added and removed as splicing progresses
Which process contributes to genetic diversity in eukaryotes?
Intron retention during splicing
What is the function of the carboxyl terminal domain (CTD) of the largest subunit of RNA Pol II in pre-mRNA processing?
Acts as an assembly platform and regulator of pre-mRNA processing machinery
Which process can explain why human cells produce over 100,000 distinct polypeptides despite having around 22,000 genes?
Alternative splicing
What is the major role of alternative splicing in human genes?
Expands the genetic diversity of an organism
Which of the following is NOT a mechanism for producing alternative transcripts?
Alternative 5' capping sites
Which process allows the expression of select transcripts in a tissue-specific manner?
Alternative splicing
What can occur when more than one sequence upstream of a gene can initiate transcription?
Alternative promoters
How do thyroid cells and neuronal cells differ in their processing of the CT/CGRP gene?
Neuronal cells splice out exon 4 to produce CGRP, while thyroid cells use exon 4 to produce calcitonin.
What percentage of human genes are thought to undergo alternative splicing?
~70%
What is the role of RNA Triphosphatase in mRNA processing?
Removing a phosphate from the 5¢ end of the mRNA
What is the function of Guanylyl transferase in mRNA capping?
Joining a guanine monophosphate to the mRNA by a 5¢-to-5¢ triphosphate linkage
Which enzyme adds 20 to 200 adenines to the 3¢ end of pre-mRNA during polyadenylation?
Poly (A) Polymerase (PAP)
What is the purpose of polyadenylation in mRNA processing?
Facilitates transport of mRNA out of the nucleus
What is the main function of the 5¢ cap added to mRNA?
Essential for binding the ribosome on mRNA
What is the function of Torpedo RNase in transcription termination?
Digests residual transcript attached to RNA Polymerase II
What happens after 3¢ cleavage and polyadenylation in transcription termination according to the Torpedo Model?
RNA Polymerase II remains attached to residual transcript
What do introns represent in pre-mRNA processing?
Regions that must be removed to form mature mRNA
Test your knowledge on the spliceosome, an RNA-protein complex responsible for removing introns from pre-mRNA through a process called splicing. Learn about the composition of the spliceosome, including the five snRNPs (U1, U2, U4, U5, and U6), and how it undergoes dynamic changes during splicing reactions.
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