BCHM 4360 EXAM 3 NEWEST 2025 ACTUAL
EXAM COMPLETE 180 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
|ALREADY GRADED A+||BRAND NEW!!
What are some short sequence motifs that the spliceosome
recognizes for splice sites? - ANSWER--the 5' and 3' splice sites
and a branch-point nucleotide within the intron (like the A in
Group II introns) and a polypyrimidine region before the 3' splice
site
Usually, introns have __ and __ at their ends. - ANSWER--GU,
AG
What are the 5 steps of how the spliceosome works? - ANSWER-
-1. The 5' splice site is recognized by U1 and other sequences
are bound by non-snRNPs.
2-3. The rest of the splicing apparatus binds, sometimes
displacing other factors, including the branch-point-binding protein
(BPP).
4. The pre-mRNA rearranges, the first transesterification reaction
occurs and the lariat forms.
5. Other rearrangements then bring the two exons together for the
second transesterification.
, BCHM 4360 EXAM 3 NEWEST 2025 ACTUAL
EXAM COMPLETE 180 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
|ALREADY GRADED A+||BRAND NEW!!
What is the EJC? - ANSWER--exon junction complex, left at
splice junctions after splicing and marks the transcript as
processed and interacts with export and translation proteins
What is the difference between cis and trans splicing? -
ANSWER--Cis splicing is where exons in the same molecule are
joined together.
Trans splicing is unusual, and joins exons from different RNA
molecules.
PRP8, ATPases, and SR proteins are all proteins involved in
splicing. What do they do? - ANSWER---PRP8, found near the
active site of the assembled spliceosome, thought to be important
in catalysis.
-ATPases, which probably help with structural rearrangements
and promote lariat and mRNA release after processing.
-SR proteins (named after serine/arginine repeats) are thought to
help recruit spliceosome components in the splice sites
What is alternative splicing? - ANSWER--different combinations of
exons can be used, yielding more than one mature mRNA
, BCHM 4360 EXAM 3 NEWEST 2025 ACTUAL
EXAM COMPLETE 180 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
|ALREADY GRADED A+||BRAND NEW!!
Most exons are ____________ (must be included), but some are
__________ exons (can be included or not) - ANSWER--
constitutive, regulated
What are cryptic splice sites? - ANSWER--False splice sites that
occur as a result of the simplicity of the sequences defining intron-
exon junctions
What are the two methods for how the spliceosome recognizes
only true splice sites and not cryptic splice sites and how do they
work? - ANSWER--1. Exon definition (mammals)
-The 5' and 3' ends of an exon are brought together by
interactions between the U1 and U2 complex. Mutations at a 5'
splice site would result in exon exclusion. The exon is typically
marked with SR proteins and the introns bound with hnRNPs,
which masks cryptic splice sites.
2. Intron definition
-Introns are defined by interactions between 5' and 3' bound
factors. Mutations at a 5' splice site would reslut in intron
inclusion.
Describe the similarities between the exon definition and intron
definition models? - ANSWER---In both models, the final splicing
, BCHM 4360 EXAM 3 NEWEST 2025 ACTUAL
EXAM COMPLETE 180 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
|ALREADY GRADED A+||BRAND NEW!!
complex must be one in which the 5' and 3' complexes interact
with one another across the intron
-In both models, the 5' and 3' splice sites are marked as they are
transcribed, facilitated by RNA Polymerase and splicing
components
RNA sequence elements that positively affect splicing are called
splicing _________. _________ sequences have the opposite
effect. Both can either be intronic or exonic (ISS/ESS) -
ANSWER--enhancers, silencer
What is an example of a silencer protein. - ANSWER--
Polypyrimidine tract binding protein (PTB) which binds to intron
elements and silences neighboring weak introns
True or False: Specific nucleotides can be modified, inserted, or
deleted during the processing of mRNA. - ANSWER--True
What are the two main common RNA edits? - ANSWER--1.
Deamination of adenosine to inosine
2. Deamination of cytidine to uridine
EXAM COMPLETE 180 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
|ALREADY GRADED A+||BRAND NEW!!
What are some short sequence motifs that the spliceosome
recognizes for splice sites? - ANSWER--the 5' and 3' splice sites
and a branch-point nucleotide within the intron (like the A in
Group II introns) and a polypyrimidine region before the 3' splice
site
Usually, introns have __ and __ at their ends. - ANSWER--GU,
AG
What are the 5 steps of how the spliceosome works? - ANSWER-
-1. The 5' splice site is recognized by U1 and other sequences
are bound by non-snRNPs.
2-3. The rest of the splicing apparatus binds, sometimes
displacing other factors, including the branch-point-binding protein
(BPP).
4. The pre-mRNA rearranges, the first transesterification reaction
occurs and the lariat forms.
5. Other rearrangements then bring the two exons together for the
second transesterification.
, BCHM 4360 EXAM 3 NEWEST 2025 ACTUAL
EXAM COMPLETE 180 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
|ALREADY GRADED A+||BRAND NEW!!
What is the EJC? - ANSWER--exon junction complex, left at
splice junctions after splicing and marks the transcript as
processed and interacts with export and translation proteins
What is the difference between cis and trans splicing? -
ANSWER--Cis splicing is where exons in the same molecule are
joined together.
Trans splicing is unusual, and joins exons from different RNA
molecules.
PRP8, ATPases, and SR proteins are all proteins involved in
splicing. What do they do? - ANSWER---PRP8, found near the
active site of the assembled spliceosome, thought to be important
in catalysis.
-ATPases, which probably help with structural rearrangements
and promote lariat and mRNA release after processing.
-SR proteins (named after serine/arginine repeats) are thought to
help recruit spliceosome components in the splice sites
What is alternative splicing? - ANSWER--different combinations of
exons can be used, yielding more than one mature mRNA
, BCHM 4360 EXAM 3 NEWEST 2025 ACTUAL
EXAM COMPLETE 180 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
|ALREADY GRADED A+||BRAND NEW!!
Most exons are ____________ (must be included), but some are
__________ exons (can be included or not) - ANSWER--
constitutive, regulated
What are cryptic splice sites? - ANSWER--False splice sites that
occur as a result of the simplicity of the sequences defining intron-
exon junctions
What are the two methods for how the spliceosome recognizes
only true splice sites and not cryptic splice sites and how do they
work? - ANSWER--1. Exon definition (mammals)
-The 5' and 3' ends of an exon are brought together by
interactions between the U1 and U2 complex. Mutations at a 5'
splice site would result in exon exclusion. The exon is typically
marked with SR proteins and the introns bound with hnRNPs,
which masks cryptic splice sites.
2. Intron definition
-Introns are defined by interactions between 5' and 3' bound
factors. Mutations at a 5' splice site would reslut in intron
inclusion.
Describe the similarities between the exon definition and intron
definition models? - ANSWER---In both models, the final splicing
, BCHM 4360 EXAM 3 NEWEST 2025 ACTUAL
EXAM COMPLETE 180 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
|ALREADY GRADED A+||BRAND NEW!!
complex must be one in which the 5' and 3' complexes interact
with one another across the intron
-In both models, the 5' and 3' splice sites are marked as they are
transcribed, facilitated by RNA Polymerase and splicing
components
RNA sequence elements that positively affect splicing are called
splicing _________. _________ sequences have the opposite
effect. Both can either be intronic or exonic (ISS/ESS) -
ANSWER--enhancers, silencer
What is an example of a silencer protein. - ANSWER--
Polypyrimidine tract binding protein (PTB) which binds to intron
elements and silences neighboring weak introns
True or False: Specific nucleotides can be modified, inserted, or
deleted during the processing of mRNA. - ANSWER--True
What are the two main common RNA edits? - ANSWER--1.
Deamination of adenosine to inosine
2. Deamination of cytidine to uridine
