Why we need a plasmid for r-DNA technology
A plasmid has a site necessary for replication of genetic material know as the origin of replication (ori) since gene of interest (GOI) is just a segment of DNA it only posseses the sequence of interest and lacks an ori site, due to this it will not be able to replicate by itself. Replication of GOI is important for product formation in r-DNA technology (mostly protien) as when the host cells divides the GOI is duplicated and is transferred to both daughter cells. This way the number of recombinant cells will increase hence producing more of the final product.