Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition Lac– strain, called lac3–, is linked to the Tn5 insertion. From a strain carrying the Tn5 insertion and lac3– mutation you isolate an F’ that caries a region of the chromosome that includes both Tn5 and the linked Lac region. Introduce this F’ into an F– strain carrying lac1– by selecting for Kanr. These merodiploids express ß-galactosidase normally. What does this result tell you about the relationship between the lac3– and lac1- mutations?  

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#Question id: 3850

#SCPH01 Biochemistry

The RNA molecule produced in RNA synthesis is:

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#Question id: 4193

#SCPH28 | Zoology

Chain elongation consists of three steps: (1) positioning the correct aminoacyl-tRNA to the A site, (2) forming the peptide bond and (3) __.

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#Question id: 4952

#SCPH06 I Botany

Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth. Which of these questions is currently the most problematic and would have the greatest impact on our understanding if we were able to answer it?

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#Question id: 19630

#SCPH05 I Biotechnology

Which of the following is the weakest base?

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#Question id: 5742

#SCPH28 | Zoology

When an allotetraploid (AABB) is backcrossed to one of its progenitor species (AA), a sterile progeny is produced.  The genomic composition of this sterile individual can be best represented by