What is a plasmid?
A piece of DNA that is circular in shape, most common in bacteria. It codes for special characteristics of the bacteria that are not vital. A plasmid can be passed from one bacterial cell to another where as the rest of the bacterial genome can't.
Plasmids are classified as: 1. F plasmid 2. R plasmid 3. Col plasmid F plasmids for fertility factor, it transfers its plasmid to the non fertile making it fertile. R plasmid for certain antibiotic resisitivity..for eg, ampicillin resistance. Col are certain proteins which when produced doesnt let other organisms to invade its cell.
Every plasmid has a copy number that reflects the average number of copies of a certain plasmid inside a host cell(usually a bacterial cell). So a multicopy plasmid, exist in multiple copies in any given bacteria. It is believed that the higher the copy number is, the more efficient the plasmid is at replicating itself.
Ampicillin is an antibiotic that is usually used as a reporter gene in cloning. A plasmid containing the ampicillin resistance gene (as well as another target gene within the plasmid) is introduced into the bacterial host. If the bacterium has taken up the plasmid and is expressing the plasmid, it will be resistant to ampicillin. LB is used as a growth medium and ampicillin to verify the plasmid is within the bactrium. No growth means…