Question

In a conjugation experiment between between the two cells shown here, transfer of both the leu+ and thr+ genes could be monitored by growing the recipient cells on media ______.

a-lacking leucine, but containing threonine
b-containing both leucine and threonine
c-containing leucine, but lacking threonine
d-lacking both leucine and threonine

Answer 1

To monitor the transfer of the leu+ and thr+ genes in a conjugation experiment, recipient cells should be grown on media lacking both leucine and threonine.

Step-by-step explanation:

In a conjugation experiment between two Escherichia coli cells, monitoring the successful transfer of both the leu+ (leucine+) and thr+ (threonine+) genes can be done by growing the recipient cells on media that lacks both amino acids. This is because the recipient cell will only be able to grow on this media if it has successfully acquired the genes necessary for synthesizing leucine and threonine, which would confirm the transfer of those genes during the conjugation experiment. Therefore, the correct answer to fill in the blank is d-lacking both leucine and threonine.