plasmíd

A plasmid is a small, circular, double-stranded DNA molecule that is distinct from a cell's chromosomal DNA. Plasmids naturally exist in bacterial cells, and they also occur in some eukaryotes. Plasmids are typically replicated by the same machinery as the host cell's chromosome.

Plasmids serve several purposes in their host cells. In bacteria, they can carry genes that confer advantageous traits such as antibiotic resistance, virulence factors, or metabolic capabilities. These genes can be beneficial to the host organism's survival and reproduction in certain environments. Plasmids can be transferred between bacteria through a process called conjugation, which allows for the rapid spread of these advantageous traits within a population.

In biotechnology, plasmids are widely used as vectors for gene cloning and manipulation. Scientists can insert foreign DNA into a plasmid, which then acts as a vehicle to carry and replicate this DNA within a host organism, often bacteria or yeast. This process allows for the amplification of specific genes, the production of recombinant proteins, and the study of gene function. The ability to easily isolate, modify, and reintroduce plasmids makes them indispensable tools in molecular biology and genetic engineering. Their small size and circular nature facilitate their manipulation and replication.