Practice Questions

TLS Online TPP Program

#Question id: 5298

Four E. coli strains of genotype a+ b− are labeled 1, 2, 3, and 4. Four strains of genotype a− b+ are labeled 5, 6, 7, and 8. The two genotypes are mixed in all possible combinations and (after incubation) are plated to determine the frequency of a+ b+ recombinants. The following results are obtained, where M = many recombinants, L = low numbers of recombinants, and 0 = no recombinants. On the basis of these results, assign a sex type (either Hfr, F+, or F−) to each strain

#Unit 8. Inheritance Biology

Thus strains 2, 3, 4 and 7 are F−. Strains 1 and 8 are F+, and strains 5, and 6 are Hfr.
Thus strains 3, and 7 are F−. Strains 1, 2 and 8 are F+, and strains 4, 5, and 6 are Hfr.
Thus strains 2, 3, and 7 are F−. Strains 1, 6 and 8 are F+, and strains 4 and 5 are Hfr.
Thus strains 2, 3, and 7 are F−. Strains 1 and 8 are F+, and strains 4, 5, and 6 are Hfr.