Question

Plasmids are extra-chromosomal circular DNA molecules :

• A. which have their own point of replication and can replicate independently
• B. which have their own point of replicant but cannot replicate independently
• C. which do not have their own point of replication and cannot replicate indepen dent of bacterial chromosomal DNA
• D. none of the above

Answer 1

Answer: (A)

Plasmids are extra chromosomal, molecules of DNA that replicate independently of bacterial chromosomes. They are normally closed, circular, supercoiled, $22-210\,kb$ in size. Plasmids are used as vector for cloning and genetic engineering.