Genetics Chp 12
Promoter-Proaryotes
-10 TATA
Promoter-Eukaryotes
-25 TATA for mRNA
5' - 3' -10 sequence -35 sequence Rho terminator cDNA of insulin
-35 sequence -10 sequence cDNA of insulin Rho terminator
initiation-Eukaryotes
5 general factors
Which of the following modifications occur to a eukaryotic pre-mRNA?
5' cap added, removal of introns, 3' poly A tail added.
The figure shows an intron flanked by two exons. Splicing requires three sites to be recognized by the spliceosome, the 5' splice site, the 3' splice site, and the branch site. Label these sequences on the figure.
5', branch 3'
RNA polymerase I
Forms phosphodiester bonds
Initiation
Holoenzyme binds to promoter
The enzyme that accomplishes transcription is termed
RNA polymerase.
Termination-Proaryotes
Rho dependent and independent models
initiation-Proaryotes
Sigma factor needed
Which is a correct statement about Rho independent termination?
It requires a stem loop to form in the RNA.
polyA addition- Presence in prokaryotes
Occasional
enhancer
cis-acting
promoter
cis-acting
silencer
cis-acting
Tailing-Eukaryotes
common for stability
Splicing-Eukaryotes
common in mRNA genes
capping-Eukaryotes
common on mRNA
RNA editing occurs when bases are____.
deaminated
capping-Proaryotes
does not occur
The DNA probe must be from an___.
exon
Which of the following occurs first in transcription?
formation of a holoenzyme
rRNA genes in some protozoa have_______ introns.
group I
Where does splicing occur in the cell?
in the nucleus
Which of the following is correct regarding sigma factor?
it recognizes the promoter region
If the control had been performed and the results were 339 cpm, then the conclusion would be that the RNA the probe could bind to is in the___ but not ___
liver, spleen and brain.
RNA editing occurs in____ trypanosomal mitochrondrial mRNAs.
many
While group I and II introns can self splice, in cells the process is often helped by proteins called_________.
maturases
Introns in _______ are not self splicing.
pre-mRNAs
Tailing-Proaryotes
promotes degredation
Spacer regions removed
rRNA
Transcribed mainly by RNA pol 1
rRNA
splicing- Presence in prokaryotes
rare
Splicing-Proaryotes
rare; self splicing
In group I and group II introns, the RNAs act as_________, which means they are RNAs with enzymatic activity.
ribozymes
Group I and group II introns are ______
self-splicing
RNA editing is the process where the base______ of a transcribed RNA can be changed.
sequence
Splicing joins together
two exons.
Deamination of cytosine results in___ and with adenine it results in____.
uracil, inosine
RNA polymerase III
uses DNA as a template
RNA polymerase II
uses ribonucleotides
RNA polymerase-Proaryotes
1 polymerase
Arrange the following in the proper sequence in which they occur during RNA splicing. 1. Lariat is formed 2. U2 binds to branch site 3. 3' splice site is cut
2,1,3
How many RNA polymerases are there in eukaryotes?
3
RNA polymerase-Eukaryotes
3 polymerases
polyA addition - Defn
A's added to 3' end
Elongation factors dissociate from RNA Pol2
Allosteric Model
RNA Pol 2 is destabalized
Allosteric Model
Termination factors may bind to RNA pol 2 complex
Allosteric Model
RNA Editing - Defn
Change of base in sequence
splicing - Defn
Cleavage and joining of RNA
Processing - Defn
Cleavage into smaller RNAs
5'-capping- Presence in eukaryotes
Common
Base modification - Presence in eukaryotes
Common
Base modification - Presence in prokaryotes
Common
Processing- Presence in eukaryotes
Common
Processing- Presence in prokaryotes
Common
RNA editing- Presence in eukaryotes
Common
polyA addition- Presence in eukaryotes
Common
splicing- Presence in eukaryotes
Common
Base modification - Defn
Covalent modification of base
Which of the following best describes transcription?
DNA -> RNA
Elongation
DNA and polymerase in open complex
5' capping- Presence in prokaryotes
Does not occur
RNA Editing- Presence in prokaryotes
Does not occur
A eukaryotic promoter will be functional in prokaryotic cells
F
A precursor tRNA molecule must be cut with exonucleases to produce a mature tRNA
F
A prokaryotic promoter will be functional in eukaryotic cells
F
All RNAs undergo RNA editing
F
All transcribed RNAs are translated
F
Eukaryotic pre-mRNA can be used for protein expression in prokaryotes
F
Polyadenylation primarily occurs in the cytoplasm.
F
Pre-mRNA would be useful for an in vivo translation assay
F
The 3' splice site contains a GU, whereas the 5' splice site contains an AG.
F
The terminator of a gene is located upstream of the coding region.
F
Unwinding of the DNA during transcription is the result of the activity of a helicase enzyme downstream of the RNA polymerase.
F
5' capping - Defn
Methylated guanine added to 5' end
Is the promoter sequence part of the DNA that is transcribed?
Neither the -35 nor the -10 sequences are present on the new transcript.
Termination
Polymerase stops synthesizing copy of DNA template
Elongation
Polymerase synthesizes copy of DNA template
The most important control that is missing are the results of a sample with no____ added.
RNA
Termination
RNA forms stem loop structure for this to occur
A 7-methylguanosine cap is necessary for an mRNA to leave the nucleus.
T
Alternative splicing is more important in yeast than humans.
T
In Trypanosomes, RNA editing involves the addition and deletion of uracil nucleotides.
T
It is possible to get more than one protein product from a eukaryotic pre-mRNA.
T
Mature mRNA from a eukaryotic cell will not be identical to the primary transcript
T
Mature mRNA from a prokaryotic cell will be identical to the genomic sequence
T
Rna polymerases demonstrate the statement function follows form
T
The RNA transcript being produced by the RNA polymerase is complementary to the template strand of the DNA.
T
The length of the poly A tail affects the stability of the mRNA
T
Place the sentences in the correct order for formation of the open complex at eukaryotic promoters TFIIID binds to TATA box TFIIB binds to TFIID TFIIB promotes binding of RNA polymerase II TFIIF binds to RNA pol II TFIIH acts as helicase to form open complex TFIIE and TFIIH bind to RNA pol II to form closed complex
TFIIID binds to TATA box TFIIB binds to TFIID TFIIB promotes binding of RNA polymerase II TFIIF binds to RNA pol II TFIIE and TFIIH bind to RNA pol II to form closed complex TFIIH acts as helicase to form open complex
Look at the sequences in the figure. They all represent different bacterial promoter regions. Which of the sequences listed below is the best consensus sequence for the -35 region based on these seven promoters?
TTGACA
Initiation of transcription includes
The RNA polymerase holoenzyme binds to the promoter.
Termination-Eukaryotes
Torpedo and allosteric models
Exonuclease degrades transcript in 5' to 3' direction
Torpedo model
Exonuclease stops RNA Pol
Torpedo model
RNA Pol 2 is physically removed from DNA
Torpedo model
RNA downstream from polyA sequence is cleaved
Torpedo model
Look at the promoter for the gene shown to the left. Where does transcription start?
Transcription starts at the +1 site.
For a protein encoding gene, what marks the start and end of the DNA region that will be transcribed?
a promoter and a terminator
Transcription factors are proteins that can increase the rate of transcription. can decrease the rate of transcription. bind to DNA.
all of these are correct
RNA editing can result in different ___ as well as new ___.
amino acids, stop codons
The snRNPs are also called
snurps
Since the control is missing, the results of the _____ cannot be interpreted as positive or negative.
spleen and brain
A_________, composed of many proteins and RNAs is required for pre-mRNA splicing to occur.
spliceosome
Extensive base modification
tRNA
Processed by RNaseD
tRNA
Processed by RNaseP
tRNA
Processed by endonuclease
tRNA
Processed by exonuclease
tRNA
Transcribed by RNA pol 3
tRNA
The Rho protein is involved in the _____ stage of transcription.
termination
RNA polymerase
trans-acting
TFIID
trans-acting
transcription factors
trans-acting
RNA polymerase III
transcribes 5s rRNA and tRNA
RNA polymerase II
transcribes mRNA
RNA polymerase III
transcribes most rRNA
