The MRNA for a mammalian peptide that enhances electrolyte transfer to reduce paralysis was spliced then reversed transcribed and the CDNA ligated into a phage and transfected into host bacteria cells. The host then transcribed and translated this. The protein product however was non-functional. What is the most probable reason for this result? A. Absence of post-transcriptional modification in bacterial cells B. Differences in the post-translational mechanisms in eukaryotes and prokaryotes. C. Differences in the translational mechanisms involved in prokaryotes, e.g. 70 S ribosome vs 80S ribosome. D. The MRNA did not contain a promoter region to allow peptide translation. E. Insertion of portions of the phage DNA which added sequences for amino acids changing the function of the protein product.

The MRNA for a mammalian peptide that enhances electrolyte transfer to reduce paralysis was spliced then reversed transcribed and the CDNA ligated into a phage and transfected into host bacteria cells. The host then transcribed and translated this. The protein product however was non-functional. What is the most probable reason for this result? A. Absence of post-transcriptional modification in bacterial cells B. Differences in the post-translational mechanisms in eukaryotes and prokaryotes. C. Differences in the translational mechanisms involved in prokaryotes, e.g. 70 S ribosome vs 80S ribosome. D. The MRNA did not contain a promoter region to allow peptide translation. E. Insertion of portions of the phage DNA which added sequences for amino acids changing the function of the protein product.

Biology (MindTap Course List)

11th Edition

ISBN:9781337392938

Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Publisher:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Chapter14: Gene Regulation

Section: Chapter Questions

Problem 8TYU: Through alternative splicing, eukaryotes (a) reinforce gene inactivation (b) prevent transcription...

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The “domain-swapping” experiment that grafts the Gal4 DNA-binding domain to the LexA activation domain generates a chimeric protein that will: A) bind to the Gal4 site. B) bindto the LexA site. C) activate transcription of the LexA gene. D) activate transcription of alleukaryotic genes. E) All of the answer options are correct.
There is Hyaluronic acid synthesis occuring in Group X Strep and it is controlled by an operon with 3 genes, called hasXYZ. Based on the 3-line diagram model, a. How many ribosome binding sites are there for the protein? b. How many promoters are there for the genes? c. How many start codons are there for the protein? d. How many RNA Polymerase binding locations are there for the genes? e. How many proteins will be fully functional? f. How many mRNA strands are made?
A mechanism of control in E. coli not discussed in this chapter involves pausing of ribosomes allowing a transcription terminator to form in the mRNA. In eukaryotic fission yeast, this mechanism should a. be common since they are unicellular. b. not be common since they are unicellular. c. not occur as transcription occurs in the nucleus and translation in the cytoplasm. d. not occur due to possibility of alternative splicing.
A newly identified protein from the cells of the Panopyra plant on Pandora was shown to inhibit translation of its target genes by binding to the 5’ UTR of the mRNA and preventing ribosome binding. A possible way this inhibition may be relieved by an sRNA would be: Group of answer choices a)The sRNA acts as a silencer, suppressing the inhibitory protein and allowing translation to take place. b)The sRNA acts as a decoy, sequestering the inhibitory protein and allowing translation to take place. c)The sRNA acts as a marker, flagging the inhibitory protein for ubiquitination and allowing translation to take place.
. One mechanism by which antisense RNAs act as negative regulators of gene expression is by base pairingwith the ribosome binding site on the sense mRNA toblock translation. In a second, alternative mechanism,the act of transcribing an antisense RNA can somehow prevent RNA polymerase from recognizing thesense promoter for the same gene. Design an experimental approach that would enable you to distinguishbetween these two modes of action at a specific gene.(Hint: What would be the outcome in each case ifhigh levels of the antisense RNA were transcribedfrom a gene on a plasmid?)
You have isolated two different mutants (reg1 andreg2) causing constitutive expression of the emu operon (emu1 emu2). One mutant contains a defect in aDNA-binding site, and the other has a loss-of-functiondefect in the gene encoding a protein that binds tothe site.a. Is the DNA-binding protein a positive or negativeregulator of gene expression?b. To determine which mutant has a defect in the siteand which one has a mutation in the binding protein, you decide to do an analysis using F′ plasmids. Assuming you can assay levels of the Emu1and Emu2 proteins, what results do you predict forthe two strains (i and ii; see descriptions below) ifreg2 encodes the regulatory protein and reg1 is theregulatory site?i. F′ (reg1−reg2+emu1−emu2+)/reg1+reg2+emu1+emu2−ii. F′ (reg1+reg2−emu1−emu2+)/reg1+reg2+emu1+emu2−c. What results do you predict for the two strains(i and ii) if reg1 encodes the regulatory proteinand reg2 is the regulatory site?
Genes in both prokaryotes and eukaryotes are regulated by activators and repressors.a. Compare and contrast the mechanism of functionof a prokaryotic repressor (for example, Lac repressor) with a typical eukaryotic repressor protein(a direct repressor).b. Compare and contrast the mechanism of functionof a prokaryotic activator (for example, CAP) witha typical eukaryotic activator protein.
Eukaryotic transcription A. is independent of the presence of upstream consensus sequences. B. may involve a promoter located within the region transcribed rather than upstream. C. requires a separate promoter region for each of the three ribosomal RNAs transcribed. D. requires that the entire gene be in the nucleosome form of chromatin. E. is affected by enhancer sequences only if they are adjacent co the promoter .
a mutation in the gene encoding Dicer would most likely result in: A) a failure to break the H bonds holding the 2 strands of the siRNA together B) the inability to form H bonds betwen the siRNA and the complementary mRNA that it targets. C) the inability of the target mRNA to be cleaved upon H bonding with the siRNA D) a failure to produce siRNAs responsible for knocking down gene expression E) the failure to produce a dsRNA specific to your gene of interest
a. The original constitutive operator mutations in thelac operon were all base changes in o1. Why doyou think mutations in o2 or o3 were not isolated inthese screens?b. Explain how a mutagen that causes small insertions could produce an ocmutation.c. Would a strain with one of the ocmutations described in part (b) and also a lacIS mutation be ableto make β-galactosidase either in the presence orabsence of inducer? Explain
Through alternative splicing, eukaryotes (a) reinforce gene inactivation (b) prevent transcription of heterochromatin (c) produce related but different proteins in different tissues (d) amplify genes to meet the requirement of high levels of a gene product (e) bind transcription factors to enhancers toactivate transcription
Many bacterial genes with related functions are arranged in operons, sets of contiguous genes that are under the control of a single promoter and are transcribed together. (a) What is the advantage of this arrangement? (b) How might eukaryotic cells, which do not contain operons, ensure the simultaneous transcription of different genes?