Interrupted conjugation was used to map three genes in E. coli. The donor genes first appeared in the recipient cells at the following times: gal, 10 minutes; his, 8 minutes; pro, 15 minutes. Which gene is in the middle?

In Oswald Avery experiment, two strains of pneumococcus bacteria were used to infect mice. Explain how the experiment discovered that DNA is the transformation agent.

Draw the steps that take place during conjugation.

According to the double-strand break model, does gene conversionnecessarily involve DNA mismatch repair? Explain.

Assume you have successfully cloned a small (200 bp) fragment of DNA into the polylinker region of a pUC18 cloning vector. Describe the appearance of transformed colonies you would expect to see on each of the following plates: plain media, media containing ampicillin, media containing tetracycline, media containing ampicillin and X-Gal.

antibodies were produced in a rabbit against a 25 KDa human soluble protien. when the rabbit antiserum was used in a western blot of human soluble protiens, it detected 25-KDa protien,but also bound to protiens of 65KDa and 39 KDa.assuming that a pure protien was used to make the antibodies,how do yuo explain the results of the western blot?

a. Bacteriophage P22 was used in generalized transduction experiments to infect the Salmonella typhimurium donor strains described in the table below. The resulting phage lysates were then used to infect the S. typhimurium recipient strains listed in the table. In each cross, a phenotype was selected for one of the three genetic markers studied (str, aceA, thrA), and then replicates were performed to select the corresponding recombinants for the other two markers. The results are given in the following table: Recipient strain Selected phenotype Selected recombinants Donor strain str thrA aceAt thrA str aceA+ strs thrA+ aceA thrA+ str aceA Str Ace+ Str ThrA ThrA+ ThrA ThrA+ Ace Ace+ str: gene involved in streptomycin resistance, aceA: gene involved in the use of acetate as a carbon source, thrA: gene involved in the biosynthesis of threonine. Number 60 40 95 5 10 90 What are the selective media used in these three transduction experiments, on the one hand to obtain the selected…