RNA synthesis and processing Flashcards
1
Q
- Transcription is _______-dependent _______ synthesis.
a. DNA; DNA
b. DNA; RNA
c. RNA; DNA
d. RNA; protein
A
b. DNA; RNA
2
Q
2. The prokaryotic cells most commonly used to study transcription and translation are from a. E. coli. b. B. subtilis. c. S. cerevisiae. d. D. discoidium
A
a. E. Coli
3
Q
- RNA polymerase differs from DNA polymerase in that it
a. synthesizes new strands of RNA in a 3′ to 5′ direction.
b. is a monomeric protein.
c. can synthesize a complementary strand without the two strands of DNA being
separated.
d. does not require a primer to initiate synthesis of RNA.
A
d. does not require a primer to initiate synthesis of RNA.
4
Q
4. The DNA sequence to which an RNA polymerase binds to initiate transcription of a gene is called a(n) a. enhancer. b. promoter. c. polymerase-binding element. d. origin of transcription.
A
b. promoter
5
Q
- The regions of the DNA where RNA polymerase binds can be identified by
a. restriction mapping.
b. PCR.
c. DNA footprinting.
d. polymerase mapping.
A
c. DNA footprinting.
6
Q
- The role of the sigma (σ) factor in prokaryote transcription is to
a. unwind the DNA during transcription.
b. provide specificity to binding to the promoter region.
c. recognize the transcription initiation site.
d. terminate transcription.
A
c. recognize the transcription initiation site.
7
Q
- Transcription of a bacterial gene is initiated
a. with RNA polymerase in the closed promoter complex.
b. after release of the sigma (σ) factor
c. with RNA polymerase in the open promoter complex.
d. Both a and b
A
c. with RNA polymerase in the open promoter complex
8
Q
- Termination of transcription in E. coli occurs by
a. formation of a stem-loop structure in the RNA.
b. binding of Rho protein to the end of the mRNA.
c. binding of a sigma (σ) factor to the end of the mRNA.
d. Either a or b
A
d. Either a or b
9
Q
- The pioneering studies of gene regulation in E. coli were done in the 1950s by
a. Miller and Urey.
b. Watson and Crick.
c. Jacob and Monod.
d. Lerner and Lowe.
A
c. Jacob and Monod.
10
Q
10. One would expect the mRNA produced from the lac operon of E. coli to hybridize to the a. lac i+ gene. b. lac o region. c. β-galactosidase gene. d. All of the above
A
b. lac o region.
11
Q
11. The lac operon in E. coli is regulated by lactose, which \_\_\_\_\_\_\_ a(n) \_\_\_\_\_\_\_ of transcription. a. activates; activator b. inactivates; activator c. activates; repressor d. inactivates; repressor
A
d. inactivates; repressor
12
Q
- The lac operator consists of approximately 20 base pairs of DNA located
a. 80–100 base pairs upstream of the transcription initiation site.
b. 20–40 base pairs upstream of the transcription initiation site.
c. in a position overlapping the initiation site.
d. downstream of the transcription initiation site.
A
b. 20–40 base pairs upstream of the transcription initiation site.
13
Q
- When the operator gene has an operator constitutive mutation (oc), the gene(s) regulated by it are
a. off when they should be on.
b. always off.
c. always on.
d. regulated by the presence of the repressor.
A
c. always on.
14
Q
- Catabolite repression in E. coli
a. inhibits the breakdown of glucose in the presence of lactose.
b. is reversed by cAMP binding to catabolite activator protein.
c. inhibits the lac operon unless lactose is present.
d. is a negative feedback system.
A
b. is reversed by cAMP binding to catabolite activator protein.
15
Q
- The first step in forming a transcription complex for mRNA transcription is binding
of which of the following to the TATA box?
a. TFIA
b. TFIIA
c. TFIIIA
d. TFIID
A
d. TFIID
16
Q
- Release of RNA polymerase II to initiate transcription appears to be the direct result
of
a. binding of TAFs to the polymerase.
b. unwinding of the DNA by helicases.
c. phosphorylation of RNA polymerase by a protein kinase.
d. removal of the nucleosome occupying the promoter site.
A
c. phosphorylation of RNA polymerase by a protein kinase.
17
Q
- A reporter gene is one that
a. causes other genes to be expressed.
b. can produce a product that is easily detected when expressed under the control of a
regulatory sequence to which it has been ligated and cloned.
c. is always on.
d. is turned on by the products of other genes.
A
b. can produce a product that is easily detected when expressed under the control of a
regulatory sequence to which it has been ligated and cloned.
18
Q
- A major difference between eukaryotic and prokaryotic RNA polymerases is that
eukaryotic polymerases
a. use a set of transcription factors to bind to and initiate transcription.
b. use sigma (σ) factors to initiate transcription.
c. start from promoters.
d. start from origins of replication.
A
a. use a set of transcription factors to bind to and initiate transcription.
19
Q
- RNA polymerase I genes code for
a. mRNAs.
b. tRNAs.
c. small nuclear RNAs and small cytoplasmic RNAs.
d. ribosomal RNAs.
A
d. ribosomal RNAs.
20
Q
- Mitochondrial genes are transcribed by
a. RNA polymerase I.
b. RNA polymerase II.
c. RNA polymerases I and II.
d. a separate mitochondrial RNA polymerase.
A
d. a separate mitochondrial RNA polymerase.
21
Q
28. Enhancers usually are \_\_\_\_\_\_\_ sequences that require other \_\_\_\_\_\_\_ to regulate a gene. a. cis-acting; cis-acting sequences b. cis-acting; trans-acting factors c. trans-acting; trans-acting factors d. Both a and b
A
a. cis-acting; cis-acting sequences
22
Q
- Enhancers have been found in
a. eukaryotic cells.
b. prokaryotic cells.
c. Both a and b
d. Neither a nor b
A
c. Both a and b
23
Q
- The immunoglobulin enhancer has binding sites for _______ regulatory protein(s).
a. one specific
b. multiple positive-acting
c. multiple negative-acting
d. multiple positive- and negative-acting
A
d. multiple positive- and negative-acting
24
Q
- The large multisubunit complex that links the general transcription factors to the
gene-specific transcription factors is called
a. the transcription complex.
b. Mediator.
c. the operon.
d. TBP.
A
b. Mediator
25
32. An electrophoresis assay used to identify the sequences of DNA to which specific
regulatory proteins bind is called
a. DNA affinity chromatography.
b. an electrophoretic-mobility shift assay.
c. Western blotting.
d. Southern blotting.
b. an electrophoretic-mobility shift assay.
26
```
33. DNA sequences that prevent enhancers from acting on promoters located in adjacent
domains are called
a. isolators.
b. insulators.
c. repressors.
d. boundaries.
```
a. isolators
27
```
35. Steroid hormone receptors recognize and bind to specific DNA sequences by
________ domains.
a. zinc finger
b. helix-loop-helix
c. helix-turn-helix
d. leucine zipper
```
a. zinc finger
28
36. Helix-turn-helix transcription factor proteins are found
a. only in insects.
b. only in animal cells.
c. only in eukaryotes.
d. in both prokaryotes and eukaryotes.
c. only in eukaryotes.
29
37. The dimerization domains of leucine zipper proteins are held together by
a. hydrogen bonds.
b. attraction of unlike charged amino acids.
c. bridges formed by metal ions.
d. hydrophobic interactions.
d. hydrophobic interactions.
30
38. Eukaryotic gene repressor proteins are thought to act by binding to
a. DNA sites in competition with activating proteins.
b. specific activating proteins, preventing their binding to DNA.
c. basal transcription factors, inhibiting transcription.
d. All of the above
d. all of the above
31
4. Processing of RNA transcripts occurs
a. only in eukaryotic cells.
b. only with mRNA transcripts.
c. only with rRNA and mRNA transcripts.
d. with tRNA, rRNA, and mRNA transcripts.
b. only with mRNA transcripts.
32
61. The signal for addition of a poly-A tail to pre-mRNA is
a. UUUUUUU.
b. TTTTTTTT.
c. AAUAAA.
d. GCGCUGC.
c. AAUAAA.
33
```
66. Introns are rapidly degraded in the nucleus following excision, but the spliced
mRNAs are protected by
a. 5′ caps.
b. 3′ polyadenylation.
c. RNA binding proteins.
d. Both a and b
```
a. 5′ caps.
34
1. Transcription is
a. DNA-dependent DNA synthesis.
b. DNA-dependent RNA synthesis.
c. RNA-dependent DNA synthesis.
d. RNA-dependent protein synthesis.
b. DNA-dependent RNA synthesis.
35
2. In prokaryotes, σ factors are necessary for
a. specific binding to certain promoters.
b. low-affinity binding upstream from promoters.
c. elongation of the RNA strand to its end.
d. All of the above
a. specific binding to certain promoters.
36
3. The lac operon in E. coli is regulated by lactose, which
a. activates an activator of transcription.
b. inactivates an activator of transcription.
c. activates a repressor of transcription.
d. inactivates a repressor of transcription.
d. inactivates a repressor of transcription.
37
4. A yeast mutant shows decreased expression of the 5.8S rRNA, the 5S rRNA, and the
ACT1 mRNA. In which of the following might the mutation lie?
a. TATA-binding protein (TBP)
b. Upstream binding factor (UBF)
c. RNA polymerase III
d. TFIIB
c. RNA polymerase III
38
5. A reporter gene is used to
a. identify regulatory sequences from the upstream regions of other genes.
b. determine if a protein binds to a given sequence element.
c. determine if a gene contains introns.
d. determine the stability of a protein.
a. identify regulatory sequences from the upstream regions of other genes.
39
```
7. Which of the following is not involved in the tissue-specific expression of the
immunoglobin ( Ig) heavy chain gene?
a. Its enhancer
b. Transcriptional activators
c. Transcriptional repressors
d. RNA polymerase II
```
d. RNA polymerase II
40
```
8. Which of the following is not an example of a transcription factor DNA-binding
domain?
a. Helix-turn-helix domain
b. Acidic domain
c. Helix-loop-helix domain
d. Zinc finger domain
```
b. Acidic domain
41
9. A ribozyme is defined as
a. an enzyme in which an RNA molecule is responsible for the catalytic activity.
b. an enzyme that catalyzes the cleavage of RNA.
c. an enzyme involved in translation.
d. an enzyme that catalyzes the addition of ribose moieties[Mara: OK?] to RNA.
a. an enzyme in which an RNA molecule is responsible for the catalytic activity.
42
14. Glucose repression (or catabolite repression) is mediated by several positive
transcriptional control mechanisms. Which of the following is not one of those
mechanisms?
a. Low levels of glucose activate adenylyl cyclase, increasing synthesis of cAMP.
b. cAMP binds the catabolite activator repressor (CAP).
c. cAMP-activated CAP transcribes genes that metabolize lactose.
d. CAP binds to the α subunit of DNA polymerase.
b. cAMP binds the catabolite activator repressor (CAP).
43
15. Which of the following is not part of the transcription complex?
a. TBP
b. TAFs
c. TFIIH
d. RFC
d. RFC
44
17. Which of the following statements about cis-acting elements is true?
a. They are specific DNA sequences that control the transcription of adjacent genes.
b. Various proteins specifically recognize and bind to these cis-acting sequences.
c. They are utilized by both prokaryotes and eukaryotes.
d. All of the above.
d. All of the above.
45
18. Which of the following best describes the ability of an enhancer to mediate
transcription from very distant sites?
a. Looping of the DNA can occur, allowing the transcription factor to get into the
proximity of the RNA polymerase.
b. When needed, enhancers are spliced into a region of closer proximity to the promoter.
c. They are recognized by RNA polymerase, which bind and then slide down the
promoter toward the gene.
d. All of the above.
d. all of the above
46
19. Which of the following experimental approaches is least likely to be used in
identifying transcription factor binding sites?
a. Electrophoretic mobility shift assay
b. Northern blot
c. DNA footprinting
d. Chromatin immunoprecipitation
b. northern blot
47
20. A mutation in the leucine zipper of a transcription factor would directly prevent
a. binding of the transcription factor to its DNA recognition sequences.
b. interaction with other transcription factors in forming hetero- and homodimers.
c. binding of zinc ions and subsequent activation of the transcription factor.
d. hormone binding
a. binding of the transcription factor to its DNA recognition sequences.
