Question

In an experiment you have met, bio, thr+ and leu + bacterial strain in test tube 1; and met+, bio+, thr and leu bacterial strain in other test tube 2. Which of the following will not comply with your experimental results?

(a) Both the strains will grow in enriched media

(b) 2nd strain will grow in met absent media

(c) Mixture of two strains will grow in minimal media

(d) 1^st stain will not grow in leu absent media

The question was posed to me in an online interview.

I would like to ask this question from Gene Mapping in Bacteria by Conjugation in section Genomics : The Mapping and Sequencing of Genomes of Cytogenetics

Answer 1

Right choice is (d) 1^st stain will not grow in leu absent media

To explain I would say: In this case, the 1^st strain will have the ability to make leu as it is leu+. So it can grow in leu+ media. The ability of the mixture to grow in minimal media is due to the fact that gene transfer has taken place.