-
The 5' cap functions primarily in _______ but affects ___________.
-
The PolyA tail is found on the ___ end of mRNA.
3'
-
The polyA tail functions in...
-
Splicing is..
the removal of introns
-
splicing is essential for...
open reading frames
-
What is editing?
Changes some RNA sequences (Usually tRNA and mRNA) and makes them functional if necessary
-
What is base modification?
methylation
-
What is the function of methylation/base modification?
unknown
-
Is base modifcation necessary?
no
-
Capping is found in all ...
eukaryotic nuclear encoded mRNA
-
In order for capping to happen, the cap needs to be on...
RNA Pol II transcripts
-
Structural genes are not always ______ with their functional mRNAs
colinear
-
Coding sequences within many eukaryotic genes are seperated by ________ that aren't translated into protein
DNA sequences
-
Coding sequences within many eukaryotic genes are seperated by DNA sequences that aren't.....
translated into protein
-
what are the three steps of GTP Capping
- 1) RNA 5' triphosphate removes a phosphate
- 2) Guanotransferase hydrolyzes gtp & gmp attached to 5' end of mRNA
- 3) Methyltranserase attacks a methyl gmp to 3' end of nucleotide
-
-
methylated caps of U-RNAs are recognized by...
autoimmune diseases (rhemuatoid arthritis)
-
Organelles in prokaryotes have no....
Caps
-
Why is capping in post-transcriptional RNA the very first step?
because the capping enzyme binds to RNA pol II and caps mRNA at the 5' end immediately arter the mRNA leaves RNA Pol II.
-
Poly As are found on all mRNAs except...
histones
-
Only _______ have polyadenylation
mRNAs
-
Histone mRNAs control their 3' ends in other ways than....
polyadenylation
-
the Poly A signal in multicellular eukaryotes is (base pair sequence)
AAUAAA
-
What enzymes recognize the PolyA signal in multicellular eukaryotes?
enzymes associated with RNA Pol II
-
PolyAs regulate the gene expression by which site is
picked on open reading frame
-
The two ways the genes can be regulate on the open reading frame is...
- 1) Cleavage downstream at 3' end by endonucleases
- 2) Poly A addition -> ~100-300 A's added by PolyA Polymerase w/ no template used
-
Older RNAs have _______tails
shorter
-
The length of ______ is proportional to the shorter tails of Older RNA.
PolyA
-
The PolyA tail enhances....
translation
-
Even though the PolyA tail makes translation more efficient, it is not...
necessary
-
An exonuclease takes off 1 ______ at a time from the end
base
-
An exonuclease can take off base pairs 1 at a time from in what directions?
-
An endonuclease cleaves...
the middle of the RNA
-
PolyA does more to protect _____ rather than the Cap.
mRNA
-
Eukaryotic rRNA is synthesized in the...
nucleus
-
Protein is made in...
the cytosol
-
Ribosomes as a whole are called ___S
80
-
The large subunit of 80S is
60S
-
The small subunit of 80S is
40S
-
The components of 60S are...
- 28S
- 5S
- 5.8S
- rRNA and proteins
-
The components of 40S are...
- 18S
- rRNA and lots of proteins
-
RNA Pol I transcribes...
all rRNA except 5S rRNA
-
After translation of rRNA in the cytoplasm, RNA proteins move back to the...
nucleolous
-
After translation of rRNA in the cytoplasm, RNA proteins move back to the nucelolous for assembly into...
large and small subunits
-
After translation of rRNA in the cytoplasm, what generally happens to the RNA proteins
move back to the nucleolous to for assembly into large and small subunits
-
The newly made subunits that were assembled in the nucleous after the translation of rRNA move back to the..
cytoplasm
-
The newly made subunits that were assembled in the nucleous after the translation of rRNA move back to the cytoplasm for...
translation of other mRNAs
-
RNA Pol II makes .....
mRNAs
-
RNA Pol II makes mRNAs for...
ribosomal proteins
-
What does RNA Pol III?
5S rRNA
-
What kind of elements are typically recognized in the Open Reading Frames?
cis elements
-
what are the trans factors of the open reading frames?
- ribosomes
- helicase (melts DNA BPs)
- tRNAs
- enlongation factors (eEF)
- Initiation factors (IF)
- Release factors (RF)
-
what are the substrates of the open reading frames?
Amino acids, ATP, GTP
-
ATP is _____ in translation
burned
-
What are the five steps to Eukaryotic Translation?
- 1) recognition of CAP by eIF4
- 2) PolyA binding protein on PolyA tail associates w/ EIF4
- 3) Incomplete ribosome with 40S, moves downstream to AUG
- 4) 60S associates
- 5) Translation initiation
-
EIF4 IFs is responsible for recruiting ______ to the ribosomal initiation complex
mRNA
-
EIF4 IFs is responsible for recruiting mRNA to the...
ribosomal initiation complex
-
Eukaryotic mRNAs do NOT have a ______ sequence.
Shine-Delgarno
-
Eukaryotic mRNAs do NOT have a shine-Delgarno sequence, which is why they need ___ to help them bind to ribosomes
IFs
-
Eukaryotic mRNAs do NOT have a shine-Delgarno sequence, which is why they need IFs to help them bind to...
ribosomes
-
What kind of elements affect translation?
cis
-
the 2' Structure (stem/loop sequence) in mRNA located upsteam close to AUG causes 40S ribosomes to ....
pause
-
the 2' Structure (stem/loop sequence) in mRNA located upsteam far from AUG causes 40S ribosomes to pause to give ___ time to associate
60S
-
the 2' Structure (stem/loop sequence) in mRNA located upsteam close to AUG causes 40S ribosomes to pause to give 60S time to....
associate
-
if the 2' structure is downstream and close to the cap, it will...
block the binding of EIF4
-
if the 2' structure is downstream and close to the cap, it will block the binding of EIF4 and ____ won't bind.
ribosomes
-
It is necessary for 5' untranslated region of sufficient length to be present is ____ bps and ______ of the CAP
- Greater than or equal 40 bps (nucleotides)
- upstream
-
When is the mRNA destabilized?
When PolyA binding protein can no longer bind close to shortened poly A tail
-
When PolyA binding protein can no longer bind close to shortened poly A tail, the mRNA is ...
destabilized
-
RNA transcripts can be modified in a variety of ways, which include... (6)
- processing
- splicing
- 5ʹ capping
- 3ʹ polyA tailing
- RNA editing
- base modification
-
RNA processing is when...
The cleavage of a large RNA transcript into smaller pieces. One or more of the smaller pieces becomes a functional RNA molecule.
-
RNA processing occurs for...
rRNA and tRNA transcripts in prokaryotes and eukaryotes
-
RNA splicing is..
The RNA is cleaved at two sites, which allows an internal segment of RNA, known as an intron, to be removed. After the intron is removed, the two ends of the RNA molecules are joined together.
-
5' capping is when...
The attachment of a 7-methylguanosine cap (m7G) to the 5ʹ end of mRNA. The cap plays a role in the splicing of introns, the exit of mRNA from the nucleus, and the binding of mRNA to the ribosome.
-
RNA splicing occurs where?
- eukaryotic pre-mRNAs
- rRNAs
- tRNAs
- few bacterial RNAs
-
Where does capping occur?
Capping occurs on eukaryotic mRNAs
-
3' PolyA tailing is...
The attachment of a string of adenine-containing nucleotides to the 3ʹ end of mRNA at a site where them RNA is cleaved (see upward arrow). It is important for RNA stability and translation in eukaryotes.
-
3' polyA tailing occurs where?
on eukaryotic mRNAs and occasionally bacterial RNAs
-
RNA editing is..
The change of the base sequence of an RNA after it has been transcribed.
-
RNA editing occurs where?
occasionally amond eukaryotic RNAs
-
What is RNA base modification?
The covalent modification of a base within an RNA molecule.
-
Where does base modification occur?
tRNAs in prokaryotes and eukaryotes
-
Group I and II introns are removed by....
self-splicing
-
Pre mRNA introns are removed....
via a spliceosome
-
If RNA Polymerase I were missing from a eukaryotic cell, what types of genes would not be transcribed?
Ribosomal RNA (5.8S, 18S, and 28S)
-
If RNA Polymerase II were missing from a eukaryotic cell, what types of genes would not be transcribed?
All of the mRNA and certain snRNA genes
-
If RNA Polymerase III were missing from a eukaryotic cell, what types of genes would not be transcribed?
All of the tRNA genes and the 5S rRna genes
-
how would eukaryotic transcriptional initiation be affected if TFIIB were missing?
RNA polymerase would not be bound to the core promoter.
-
how would eukaryotic transcriptional initiation be affected if TFIID were missing?
TFIID contains the TATA-binding protein. If it were missing, RNA polymerase would not bind to the TATA box
-
how would eukaryotic transcriptional initiation be affected if TFIIH were missing?
The formation of the open complex would not take place.
-
What does it mean to say that gene expression is colinear?
A gene is colinear when the sequence of bases in the coding strand of the DNA corresponds to the sequence of bases in the mRNA
-
Why aren't a lot of eukaryotic genes colinear?
because they contain introns that are spliced out of the pre-mRNA
-
How can you tell which strand is the coding strand?
has TATAAT at 5' location in right orientation
|
|
