Question

Plasmids are suitable vectors of gene cloning because

• A. These can shuttle between prokaryotic and eukaryotic cells.
• B. These are small circular DNA molecules with their own replication origin site.
• C. These are small circular DNA molecules, which can integrate with host chromosomal DNA.
• D. These often carry antibiotic resistance genes.

Answer 1

The correct option is B These are small circular DNA molecules with their own replication origin site.

• Plasmids are small, self-duplicating, double-stranded, covalently closed and super-coiled, extra-chromosomal DNA circles, found in most species of bacteria and some species of yeasts.
• They have their own replication origin site, a selectable marker, and a restriction or cloning site.
• The insertion of foreign DNA at or near the cloning site neither inactivates the markers nor disrupts the replication of the plasmid.

So the correct option is 'B'.