what is a plasmid

A plasmid is a small, extrachromosomal DNA molecule found in bacterial cells and some other organisms. It is typically a circular, double-stranded DNA molecule that is physically separated from the chromosomal DNA and can replicate independently. Plasmids often carry genes that benefit the survival of the organism, such as antibiotic resistance genes, and they can be passed from one cell to another. In the laboratory, plasmids are widely used as vectors in molecular cloning, allowing the replication of recombinant DNA sequences within host organisms