Download Block 1: Genetics Dr. McKinney Test 1: Transcription (4) The order

Block 1: Genetics
Dr. McKinney
Test 1: Transcription (4)
1.
The order in which prokaryotic and eukaryotic transcription occurs from beginning to end is
a. formation of peptide bond, binding of aminoacyl-tRNA to A site, translocation of peptidyl-tRNA
b. binding of aminoacyl-tRNA to A, formation of peptide bond, translocation of peptidyl-tRNA
c. termination, elongation, initiation
d. initiation, elongation, termination
2. The purpose of the sigma factor in transcription is
a. to help DNA polymerase recognize promoter regions on the DNA to be transcribed
b. to help RNA polymerase II recognize promoter regions on the DNA to be transcribed
c. to direct the core enzyme of RNA polymerase to the proper promoter region during eukaryotic transcription
d. to direct the core enzyme of RNA polymerase to the proper promoter region during prokaryotic transcription
3. Transcription is coupled to translation in prokaryotes. This means that….. and it can occur because….
a. mRNA can be transcribed at the same time that DNA is replicated because they use the same polymerases.
b. translation of the mRNA transcript can begin before it has been completely transcribed by RNA polymerase, and it
occurs because both processes take place in the cytosol due to the lack of a nuclear membrane.
c. translation by the RNA polymerase can begin while transcription is still occurring on the mRNA transcript due to the
fact that both processes occur in the cytoplasm because prokaryotes lack a nucleus.
d. DNA replication, mRNA transcription, and translation can all occur simultaneously because they all occur within the
nucleus.
4. The levels of regulation in bacterial gene expression include all of the following except:
a. post-translational control via chemical modifications
b. transcriptional control
c. apoptosis
d. translational control
5. Match the following components of transcription with their correct descriptions:
a. template/ antisense/ noncoding strand
b. nontemplate/ sense/ coding strand
c. promoter region
d. consensus sequence
e. Enhancers
i. consist of most commonly found sequence of bases in a give region of all DNAs tested; examples include the
Prinbow box (TATAAT), TATA box, CAAT box
ii. the strand that is read by the RNA polymerase in the 3’-5’ direction; this will be complementary to the new
mRNA transcript
iii. this strand will contain the same sequence as the mRNA that is transcribed, except that the DNA will contain
thymine and the RNA, uracil.
iv. the region to which RNA polymerse binds; contains consensus sequences which guide its binding
v. DNA sequences found in eukaryotes that function in the stimulation of the transcription rate; they can be
located many bp up/downstream from start site
6. T/F: the DNA template is copied/read in the 5’3’ direction and the RNA chain grows in the 3’5’ direction.
7. The proper sequence of events at the promoter region for initiation of transcription is as follows:
a. TFIIA and TFIIB bind TFIID binds the TATA box RNA polymerase binds with TFIIF initiation complex
completed by addition of TFIIE, TFIIJ, and TFIIH ATP is used to activate RNA pol
b. ATP used to activate RNA polTFIID binds TATA box TFIIA and TFIIB bind RNA pol binds to complex with
TFIIF Initiation complex completed by addition of TFIIE, TFIIJ, and TFIIH
c. TFIIA and TFIIB bind TFIID binds TATA box RNA pol activated by ATP TFIIE, TFIIJ, and TFIIH bind RNA
Pol and TFIIF bind
d. TFIID binds TATA TFIIA and TFIIB bind RNA pol and TFIIF bind initiation complex complete with TFIIE,
TFIIJ, and TFIIH RNA pol activated by ATP
8. T/F: The eukaryotic cell, unlike the prokaryotic cell, contains 3 RNA polymerases, which carry out gene transcription.
9. Match the eukaryotic RNA pol with its correct transcription products:
a. RNA pol I
b. RNA pol II
c. RNA pol III
i. tRNA and other small RNAs
ii. mRNA, miRNA, snRNAs
iii. rRNA
10. The consensus signal for termination is
a. TATAAT
b. polyA
c. Prinbow box
d. GC-rich regions
11. The precursor form of mRNA is
a. hnRNA
1
Block 1: Genetics
Dr. McKinney
Test 1: Transcription (4)
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
b. rRNA
c. miRNA
d. tRNA
Steps involved in mRNA transcription and processing include all of the following except:
a. removal of introns and splicing of exons
b. addition of 5’ cap for stability
c. addition of 3’ polyA tail for termination signal
d. addition of CCA sequence at the 3’ end catalyzed by nucleotidyl transferase
works to splice the exons together with accuracy and is composed of snRNPs.
a. RNA polymerase
b. DNA polymerase
c. Spliceosome
d. sigma factor
T/F: The addition of the polyA tail at the 3’ end of the transcript occurs when the RNA polymerase reads past the “stop” codon
in the coding strand and reaches an AAUAAA signal. At this point, the RNA polymerase is released, the transcript is cleaved
about 10-20 nt downstream, and a >200 nt poly A tail is added by poly(A) polymerase using the coding strand of DNA, which
contains the complementary region of >200 nt TTT sequence.
How is a newly synthesized pre-mRNA protected from degradation?
a. the addition of a 3’ polyA tail
b. the addition of a 5’ 7-methylguanosine cap
c. the addition of both a 3’ polyA tail and a 5’ 7-methylguanosine cap
d. Single stranded binding proteins
Match the following types of Eukaryotic RNA with their appropriate descriptions:
a. mRNA
b. miRNA
c. lncRNA
d. rRNA
e. tRNA
i. forms major structural complex of the ribosome + proteins
ii. carries message from DNA to ribosome for translation
iii. function in regulation of gene expression via degradation of the mRNA transcript or inhibition of translation
iv. function sin regulation of gene expression
v. acts as an adapter molecule aligning AAs with mRNA sequence held in the ribosome
T/F: A major difference between mRNA/tRNA synthesis and rRNA synthesis is the fact that mRNA/tRNA synthesis occurs
from genes located in the nucleolus, where many copies are present, and is carried out by RNA pol I.
tRNA is transcribed as a precursor that undergoes post-transcriptional processing including which of the following?
a. removal of 5’ leader sequence
b. replacement of 2 nts at the 3’ end with CCA sequence
c. chemical modifications
d. excision of introns
e. all of the above
Which of the following best describes the structure of the tRNA molecule?
a. linear sequence of RNA containing a 5’ 7-methylguanosine cap and a 3’ polyA tail
b. 45S precursor that is eventually cleaved and complexed with other RNA molecules and proteins to form globular
subunits.
c. in 2D, it is a cruciform/clover leaf structure with double stranded bonding between 3 hairpin loops, as well as a
variable loop, and a 3’ CCA
d. none of the above
is an enzyme that catalyzes the formation of cDNA from mRNA, and is used as a tool in molecular genetics
as well as retroviruses.
a. DNA polymerase
b. RNA polymerase
c. reverse transcriptase
d. nucleotidyl transferase
genomes can be exploited as vectors for Gene Therapy.
a. bacterial
b. viral
c. retroviral
d. fungal
A patient presents to the ER with severe GI problems, high fever, and liver and kidney dysfunction. You take a history and
discover that the patient recently went “shroom hunting.” What is the most likely cause of his symptoms and what is the typical
outcome for his condition?
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Block 1: Genetics
Dr. McKinney
Test 1: Transcription (4)
a.
E. coli infection from eating unwashed mushrooms. He will be better within a couple of days after an antibiotic and
fluids are administered.
b. -amanitin poison from the mushrooms. Typically, 40-90% of patients die within a few days of ingestion.
c. In a completely unrelated event, he contracted H. pylori during a mission trip he took to El Salvador from
contaminated water. He will recover within several days after being administered an antibiotic.
23. Diptheria toxin is composed of 2 subunits, A and B. The function of subunit A is to:
a. bind host membrane toxin receptor and cause receptor-mediated endocytosis of the toxin
b. bind the host membrane and cause its degradation
c. ADP-ribosylates EF2, halting protein synthesis and killing the cell.
d. ADP-ribosylates EF2, increasing rate of protein synthesis, stressing the cell and leading to apoptosis.
24. Which of the following statements concerning -Thalassemia is false?
a. it results in microcytic anemia, meaning not enough HbA is made to fill RBCs and pts with this disease will require
repeated blood transfusions and have potential Fe overload
b. is an autosomal recessive disease in which there is a mutation in the -globin gene on chromosome 11 in both parents.
c. the severity of disease depends on the mutation inherited from each parent, and this can be determined by PCR
diagnosis.
d. there is no heterozygote advantage, so a person with +o will not have protection against certain diseases.
3
Block 1: Genetics
Dr. McKinney
Test 1: Transcription (4)
1.
2.
3.
4.
5.
6.
7.
The order in which prokaryotic and eukaryotic transcription occurs from beginning to end is
a. formation of peptide bond, binding of aminoacyl-tRNA to A site, translocation of peptidyl-tRNA
b. binding of aminoacyl-tRNA to A, formation of peptide bond, translocation of peptidyl-tRNA
c. termination, elongation, initiation
d. initiation, elongation, termination
i. a & b: these are steps involved in the elongation step of translation
The purpose of the sigma factor in transcription is
a. to help DNA polymerase recognize promoter regions on the DNA to be transcribed
b. to help RNA polymerase II recognize promoter regions on the DNA to be transcribed
c. to direct the core enzyme of RNA polymerase to the proper promoter region during eukaryotic transcription
d. to direct the core enzyme of RNA polymerase to the proper promoter region during prokaryotic
transcription
i. a- DNA polymerase is only used in DNA replication
ii. b- RNA polymerase II is used in eukaryotic transcription
iii. c- the core enzyme of RNA polymerase is made up of 5 subunits and a sigma factor. The purpose of this
sigma factor is to direct the core enzyme to the correct promoter region t0 carry out transcription, however
this is the RNA polymerase used in prokaryotic transcription, not eukaryotic.
Transcription is coupled to translation in prokaryotes. This means that….. and it can occur because….
a. mRNA can be transcribed at the same time that DNA is replicated because they use the same polymerases.
b. translation of the mRNA transcript can begin before it has been completely transcribed by RNA
polymerase, and it occurs because both processes take place in the cytosol due to the lack of a nuclear
membrane.
c. translation by the RNA polymerase can begin while transcription is still occurring on the mRNA transcript due to the
fact that both processes occur in the cytoplasm because prokaryotes lack a nucleus.
d. DNA replication, mRNA transcription, and translation can all occur simultaneously because they all occur within the
nucleus.
i. a- these two processes are not coupled, and they use different polymerases.
ii. c- translation occurs via a ribosome, not a polymerase, however it is true that both of these processes occur
in the cytoplasm because prokaryotes lack a nucleus
iii. DNA replication is not coupled to transcription or translation
The levels of regulation in bacterial gene expression include all of the following except:
a. post-translational control via chemical modifications
b. transcriptional control
c. apoptosis
d. translational control
Match the following components of transcription with their correct descriptions:
a. template/ antisense/ noncoding strand
b. nontemplate/ sense/ coding strand
c. promoter region
d. consensus sequence
e. Enhancers
i. consist of most commonly found sequence of bases in a give region of all DNAs tested; examples include the
Prinbow box (TATAAT), TATA box, CAAT box (d)
ii. the strand that is read by the RNA polymerase in the 3’-5’ direction; this will be complementary to the new
mRNA transcript (a)
iii. this strand will contain the same sequence as the mRNA that is transcribed, except that the DNA will contain
thymine and the RNA, uracil. (b)
iv. the region to which RNA polymerse binds; contains consensus sequences which guide its binding (c)
v. DNA sequences found in eukaryotes that function in the stimulation of the transcription rate; they can be
located many bp up/downstream from start site (e)
T/F: the DNA template is copied/read in the 5’3’ direction and the RNA chain grows in the 3’5’ direction.
a. False: this is backwards. The polymerase will read the template strand in the 3’5’ direction and synthesize the RNA
strand in the 5’3’ end for the same reason that DNA must be synthesized in this direction—a free 3’ –OH must be
present for the phosphodiester bond to be formed.
The proper sequence of events at the promoter region for initiation of transcription is as follows:
a. TFIIA and TFIIB bind TFIID binds the TATA box RNA polymerase binds with TFIIF initiation complex
completed by addition of TFIIE, TFIIJ, and TFIIH ATP is used to activate RNA pol
b. ATP used to activate RNA polTFIID binds TATA box TFIIA and TFIIB bind RNA pol binds to complex with
TFIIF Initiation complex completed by addition of TFIIE, TFIIJ, and TFIIH
c. TFIIA and TFIIB bind TFIID binds TATA box RNA pol activated by ATP TFIIE, TFIIJ, and TFIIH bind RNA
Pol and TFIIF bind
d. TFIID binds TATA TFIIA and TFIIB bind RNA pol and TFIIF bind initiation complex complete
with TFIIE, TFIIJ, and TFIIH RNA pol activated by ATP
4
Block 1: Genetics
Dr. McKinney
Test 1: Transcription (4)
8. T/F: The eukaryotic cell, unlike the prokaryotic cell, contains 3 RNA polymerases, which carry out gene transcription.
a. True
9. Match the eukaryotic RNA pol with its correct transcription products:
a. RNA pol I
b. RNA pol II
c. RNA pol III
i. tRNA and other small RNAs (c)
ii. mRNA, miRNA, snRNAs (b)
iii. rRNA (a)
1. It’s important to not that all have the same mechanism of action but different types of promoters,
and therefore, different transcripts. Also, cell mitochondria have their own RNA polymerases. In
contrast, Prokaryotes only have ONE RNA pol to generate ALL types of RNA (m,t,rRNA). The
variety and specificity in prokaryotes comes from the sigma factors. There are many different
sigmas that recognize different promoter regions.
10. The consensus signal for termination is
a. TATAAT
b. polyA
c. Prinbow box
d. GC-rich regions
i. a. TATAAT= Prinbow box
ii. c. prinbow is a promoter consensus sequence
iii. d. GC-rich regions are promoter regions
11. The precursor form of mRNA is
a. hnRNA
b. rRNA
c. miRNA
d. tRNA
i. a-hnRNA stands for heterogeneous nuclear RNA and represents the RNA trsncript before splicing
ii. b- no
iii. c- miRNAs are often used for regulation; block the translation of target mRNA or induce its degradation
iv. d- no. just no.
12. Steps involved in mRNA transcription and processing include all of the following except:
a. removal of introns and splicing of exons
b. addition of 5’ cap for stability
c. addition of 3’ polyA tail for termination signal
d. addition of CCA sequence at the 3’ end catalyzed by nucleotidyl transferase
i. d- is a step in tRNA synthesis; the CCA is where the aminoacylt-tRNA synthetases will add the correct AA to
the tRNA molecule
ii. b- it’s important to note that this process requires folate and B12 and is one of the processes affected by
vitamin deficiencies
13.
works to splice the exons together with accuracy and is composed of snRNPs.
a. RNA polymerase
b. DNA polymerase
c. Spliceosome
d. sigma factor
i. spliceosomes recognize sequences on either side of pre-mRNA introns; GU at the 5’ end and AG at the 3’ end
(relating to the intron) [GU…..AG]= intron boundaries to be spliced out
ii. splicing reactions remove introns (noncoding regions) and connect exons. small nuclear RNAs (snRNPs)
are involved and form a lariat loop structure to take out the intron and join the exons.
14. T/F: The addition of the polyA tail at the 3’ end of the transcript occurs when the RNA polymerase reads past the “stop” codon
in the coding strand and reaches an AAUAAA signal. At this point, the RNA polymerase is released, the transcript is cleaved
about 10-20 nt downstream, and a >200 nt poly A tail is added by poly(A) polymerase using the coding strand of DNA, which
contains the complementary region of >200 nt TTT sequence.
a. False: The error in this explanation of the polyA tail addition is in the very end. The tail is added post
transcriptionally, so DNA coding strand is no longer involved, meaning there is no complementary T sequence in the
DNA coding strand signaling for the addition of the >200 A’s. Instead, polyA polymerase is a separate enzyme that
uses ATP to add As to create the polyA tail, which protects the mRNA from degradation
15. How is a newly synthesized pre-mRNA protected from degradation?
a. the addition of a 3’ polyA tail
b. the addition of a 5’ 7-methylguanosine cap
c. the addition of both a 3’ polyA tail and a 5’ 7-methylguanosine cap
d. Single stranded binding proteins
16. Match the following types of Eukaryotic RNA with their appropriate descriptions:
5
Block 1: Genetics
Dr. McKinney
Test 1: Transcription (4)
a.
b.
c.
d.
e.
17.
18.
19.
20.
21.
22.
23.
mRNA
miRNA
lncRNA
rRNA
tRNA
i. forms major structural complex of the ribosome + proteins (d)
ii. carries message from DNA to ribosome for translation (a)
iii. function in regulation of gene expression via degradation of the mRNA transcript or inhibition of translation
(b)
iv. function sin regulation of gene expression (c)
v. acts as an adapter molecule aligning AAs with mRNA sequence held in the ribosome (e)
T/F: A major difference between mRNA/tRNA synthesis and rRNA synthesis is the fact that mRNA/tRNA synthesis occurs
from genes located in the nucleolus, where many copies are present, and is carried out by RNA pol I.
a. False: rRNA synthesis occurs in the nucleolar region where there are approximately 1000 copies, linked in tandem
and separated by spacer regions, of the rRNA genes. This is carried out by pol I and results in a 45S transcript,
which is subsequently cleaved into an 18S and 28S rRNA. The 18S rRNA will combine with proteins to form the 40S
subunit and the 28S will combing with 5.8S and 5S rRNAs to form the 60S subunit. mRNAs and tRNAs are
synthesized in the nucleus.
tRNA is transcribed as a precursor that undergoes post-transcriptional processing including which of the following?
a. removal of 5’ leader sequence
b. replacement of 2 nts at the 3’ end with CCA sequence
c. chemical modifications
d. excision of introns
e. all of the above
Which of the following best describes the structure of the tRNA molecule?
a. linear sequence of RNA containing a 5’ 7-methylguanosine cap and a 3’ polyA tail
b. 45S precursor that is eventually cleaved and complexed with other RNA molecules and proteins to form globular
subunits.
c. a 2D cruciform/clover leaf structure with double stranded bonding between 3 hairpin loops, as well
as a variable loop, and a 3’ CCA
d. none of the above
i. a- describes the structure of mRNA
ii. b- describes the structure of rRNA
is an enzyme that catalyzes the formation of cDNA from mRNA, and is used as a tool in molecular genetics
as well as retroviruses.
a. DNA polymerase
b. RNA polymerase
c. reverse transcriptase
d. nucleotidyl transferase
genomes can be exploited as vectors for Gene Therapy.
a. bacterial
b. viral
c. retroviral
d. fungal
i. This is because their reverse transcriptase will reverse transcribe their RNA into DNA, which is then inserted
into host DNA and replicated/expressed when the host DNA is replicated/expressed. When this is used
therapeutically, interior viral protein coding regions are removed, gene therapy sequences are inserted, and
then non-infectious viral particles are used to deliver to the desired target.
A patient presents to the ER with severe GI problems, high fever, and liver and kidney dysfunction. You take a history and
discover that the patient recently went “shroom hunting.” What is the most likely cause of his symptoms and what is the typical
outcome for his condition?
a. E. coli infection from eating unwashed mushrooms. He will be better within a couple of days after an antibiotic and
fluids are administered.
b. -amanitin poison from the mushrooms. Typically, 40-90% of patients die within a few days of
ingestion.
c. In a completely unrelated event, he contracted H. pylori during a mission trip he took to El Salvador from
contaminated water. He will recover within several days after being administered an antibiotic.
i. -amanitin blocks eukaryotic transcription by inhibiting RNA polymerase II and mRNA synthesis
Diptheria toxin is composed of 2 subunits, A and B. The function of subunit A is to:
a. bind host membrane toxin receptor and cause receptor-mediated endocytosis of the toxin
b. bind the host membrane and cause its degradation
c. ADP-ribosylates EF2, halting protein synthesis and killing the cell.
d. ADP-ribosylates EF2, increasing rate of protein synthesis, stressing the cell and leading to apoptosis.
6
Block 1: Genetics
Dr. McKinney
Test 1: Transcription (4)
i. a-this is the function of the B subunit
ii. b- the b subunit binds the receptor, but it doesn’t cause degradation of the membrane
iii. d- A is the catalytic subunit that ADP-ribosylates the elongation factor 2, but this halts its function, it doesn’t
increase its function.
24. Which of the following statements concerning -Thalassemia is false?
a. it results in microcytic anemia, meaning not enough HbA is made to fill RBCs and pts with this disease will require
repeated blood transfusions and have potential Fe overload
b. is an autosomal recessive disease in which there is a mutation in the -globin gene on chromosome 11 in both parents.
c. the severity of disease depends on the mutation inherited from each parent, and this can be determined by PCR
diagnosis.
d. there is no heterozygote advantage, so a person with +o will not have protection against certain
diseases.
i. HbA has 2 and 2 chains. -Thalassemia is a disease where a mutation in the -globin gene causes a
deficiency in the formation of the  chain, leading to excess  chains. It results in microcytic anemia, and
severe forms (oo) typically result in death by age 20. Heterozygote advantage is seen in those who carry
one allele for the mutated gene. These individuals experience protection against malaria.
Prokaryotic
Eukaryotic
polycistronic transcription units
monocistronic transcription units
occurs in cytoplasm (DNA more
accessible)
occurs in nucleus—nucleosomes must be unwound
transcription/translation are
coupled
transcription independent of translation
one RNA polymerase required for
all
transcription
three diferent RNA polymerases required for all
transcription
sigma factor for transcription
transcription factor complexes required
RNA polymerase has 5 subunits
3 RNA polymerases may have 10-15 subunits
7