Plasmids are small circular dna molecules found in bacteria that replicate separately from chromosomes. why are plasmids essential for recombinant dna technology?

This is because DNA from a gene of interest can be inserted into a plasmid, then the modified plasmid can be inserted into a bacterial cell to make many copies of a gene of interest. Most plasmid vectors contain little more than the essential nucleotide sequences required for their use in DNA cloning: a replication origin, a drug-resistance gene, and a region in which exogenous DNA fragments can be inserted.

the cell theory states that all living things including animals, as well as plants, are made of cells.