Question

1. Explain how bacterial cloning can help increasing the amount of DNA (DNA amplification) and when it is implemented in science or in medicine. Use a diagram if needed.

Answer 1

Bacterial cloning uses Plasmids and other vectors ( autonomously self-replicating DNA molecules ) in which foreign gene ( or exogenous DNA) can be inserted. Restriction endonucleases enzyme cleaves plasmid DNA at specific sites, creating sticky ends. This is where foreign DNA fragments that need to be cloned are inserted. DNA ligase enzyme joins the ends of the DNA fragment to the ends of plasmid DNA. These recombinant plasmids are introduced into the E.coli cells. Then, the E.coli cells are cultured and grown. In the E.coli cells, the recombinant plasmids replicate autonomously. Also, when the bacterial chromosomes replicate creating daughter cells each of them contains at least one recombinant plasmid. Thus, colonies of E.coli cells are formed where the foreign gene has amplified.

• Gene cloning is useful in studying the structure and function of a gene.
• Cloned bacteria are utilized in the synthesis of vitamins, hormones and antibiotics.