How many recombinant clones must be present in a cDNA library to be 95% certain that the library contains one clone of a particular mRNA molecule representing 0.005% of the total mRNA? 

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#Question id: 18851

#Unit 13. Methods in Biology

Nickel-NTA (Ni-NTA) chromatography is a popular affinity chromatography method for the purification of histidine-tagged proteins. However, SDS-PAGE of the eluted protein can show bands in addition to your target protein. How might you improve this purification step?

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#Question id: 18852

#Unit 13. Methods in Biology

What is the starting point for selection of a suitable IEX matrix for purification of a recombinant protein?

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#Question id: 18853

#Unit 13. Methods in Biology

Your purification strategy of combinations of chromatography steps gives a protein preparation with a single band on SDS-PAGE. Which of the following would be best for determining the protein concentration (as mg/ml or molarity)?

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#Question id: 18854

#Unit 13. Methods in Biology

What properties of a protein does hydrophobic interaction chromatography exploit for purification?

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#Question id: 18855

#Unit 13. Methods in Biology

to elute target proteins from an affinity chromatography matrix, which of the following conditions would be the most appropriate?

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#Question id: 18856

#Unit 13. Methods in Biology

A scientist constructs a recombinant bacterial plasmid that contains a gene conferring resistance to the antibiotic ampicillin (amp). The scientist transforms cultures of E. coli bacteria with the recombinant plasmid, then incubates the cultures overnight on plates containing media without ampicillin (amp-) and with ampicillin (amp+).

Assuming the transformation protocol was successful, which of the following best predicts the bacterial growth pattern expected after the incubation period?