1 解决

23 浏览

• zhy158 2021-02-10

Treatment of cells with actinomycin D (a general inhibitor of transcription) prevents the formation of nucleoli following mitosis. Treatment with α-amanitin (a specific inhibitor of RNA polymerase II) does not have this effect. Why?

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39 浏览

• 24k 2021-02-10

Consider the construct (diagrammed below) in which a single enhancer (E) acts on two separate promoters (P1 and P2). How would insertion of an insulator between E and P1 affect transcription from P1 and P2? What about insertion of an insulator between P1 and P2?

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36 浏览

• Tate 2021-02-10

How would mutational inactivation of the nuclear export signal of a protein that normally shuttles back and forth between the nucleus and cytoplasm affect its subcellular distribution?

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1 解决

1 浏览

• y123456 2021-02-10

You have constructed a mutant importin β that no longer binds to Ran. What effect would expression of this mutant importin have on the traffic of proteins between the nucleus and the cytoplasm?

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1 解决

92 浏览

• eggyy 2021-02-10

You are studying a transcription factor that is regulated by phosphorylation of serine residues that inactivate its nuclear localization signal. How would mutating these serines to alanines affect subcellular localization of the transcription factor and expression of its target gene?

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1 解决

102 浏览

• leidengsen 2021-02-10

You are studying an enzyme that is activated by phosphorylation of a serine residue at position 59. How would mutation of this serine to threonine be expected to affect the enzyme's activity? What effect would you predict following mutation of the serine to alanine?

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1 解决

93 浏览

• 77565001 2021-02-10

You are interested in studying a protein expressed on the surface of liver cells. How could treatment of these cells with a phospholipase enable you to determine whether your protein is a transmembrane protein or is attached to the cell surface by a GPI anchor?

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1 解决

62 浏览

• lanhaitg 2021-02-10

Why is a member of the Hsp70 family required for selective lysosomal degradation of proteins in starved cells, but not for the degradation of proteins taken up by autophagy?

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1 解决

103 浏览

• 133****6912 2021-02-10

What effect would an inhibitor of polyadenylation be expected to have on protein synthesis in fertilized eggs?

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1 解决

87 浏览

• 1234567 2021-02-10

You wish to express a cloned eukaryotic cDNA in bacteria. What type of sequence must you add in order for the mRNA to be translated on prokaryotic ribosomes?

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1 解决

97 浏览

• sdntb 2021-02-10

A transcription factor is found to activate transcription by binding to different DNA sequences in muscle cells and liver cells. How might alternative splicing be involved in determining this tissue specificity of activator function?

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1 解决

35 浏览

• deng_yulin 2021-02-10

You are comparing the requirements for in vitro basal transcription of two polymerase II genes, one containing a TATA box and the other containing only an Inr sequence. Does transcription from these promoters require TBP or TFIID?

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1 解决

5 浏览

• 77565001 2021-02-10

You are working with two strains of E. coli. One contains a wild-type β-galactosidase gene and an i- mutation; the other contains a temperature-sensitive β-galactosidase gene and an oc mutation. After mating these strains, you assay for the production of β-galactosidase at both permissive and nonpermissive temperatures in the absence of lactose. What do you expect to find?

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1 解决

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• deng_yulin 2021-02-10

The consensus sequence of the E. coli -10 promoter element is TATAAT. You are comparing two promoters that have -10 element sequences of TATGAT and CATGAT, respectively. Which would you expect to be transcribed more efficiently?

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17 浏览

• likuniven 2021-02-10

What phenotype would you predict for a mutant mouse lacking one of the genes required for site-specific recombination in lymphocytes?

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38 浏览

• wzh1326 2021-02-10

RecA mutants of E. coli are sensitive to UV irradiation in addition to being recombination-deficient. Why?

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1 解决

59 浏览

• zoulang_2007 2021-02-10

Patients with xeroderma pigmentosum suffer an extremely high incidence of skin cancer but have not been found to have correspondingly high incidences of cancers of internal organs (e.g., colon cancer). What might this suggest about the kinds of DNA damage responsible for most internal cancers?

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1 解决

72 浏览

• 177****9261 2021-02-10

How is the fidelity of DNA replication affected by the fact that DNA polymerase adds nucleotides only to a primer strand that is hydrogen-bonded to the template?

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1 解决

45 浏览

• steelswarm 2021-02-10

Would you expect the RNA fragments synthesized by primase to be accurate copies of the template DNA? How does this affect the overall accuracy of DNA replication?

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52 浏览

• jim19970316 2021-02-10

Approximately 30,000 cDNAs have been localized on the human genome map. What is the average distance between these markers?

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