Question

In the recombinant DNA procedure using two plasmids, plasmid 67A carries a gene for resistance to the antibiotic ciprofloxacin, and plasmid 65B carries a gene for resistance to the antibiotic tetracycline. The plasmids are cut with HindIII restriction endonuclease and then mixed with DNA ligase. What is the role of tetracycline in this procedure?

1) It acts as a marker to identify the transformed cells
2) It helps in the replication of the plasmids
3) It prevents the growth of unwanted bacteria
4) It enhances the efficiency of the DNA ligase

Answer 1

Tetracycline acts as a marker to identify transformed cells in the recombinant DNA procedure. It allows scientists to distinguish between cells that have taken up the plasmids carrying the desired genes and cells that have not.

Step-by-step explanation:

The role of tetracycline in the recombinant DNA procedure using two plasmids is to act as a marker to identify the transformed cells. The plasmid 65B carries a gene for resistance to tetracycline, so when the plasmids are mixed with DNA ligase and plated on solid medium containing tetracycline, only cells that have taken up the plasmid 65B will grow. This allows scientists to distinguish between cells that have been successfully transformed with the plasmids carrying the desired genes and cells that have not.