What is a plasmid?

A plasmid is a small, circular DNA molecule commonly found in bacteria and some eukaryotic organisms. It is distinct from chromosomal DNA and is capable of independent replication. Plasmids often carry genes that can provide advantageous traits to the organism, such as antibiotic resistance, and they are frequently utilized in molecular biology for gene cloning and expression. In laboratory settings, scientists can insert genes of interest into plasmids to create recombinant DNA, which can then be introduced into host cells for various applications, such as producing proteins, studying gene functions, or developing genetic therapies.

The structure of plasmids allows for easy manipulation, making them valuable tools in biotechnology. Their circular nature and relatively small size also facilitate the transfer of genetic material, promoting genetic diversity among bacterial populations. This property is particularly important in genetic engineering and biotechnology, where plasmids can be engineered to express desired traits.

In contrast, the other options describe different entities or concepts that do not align with the definition of a plasmid:

• Large linear DNA molecules are associated with the chromosomal DNA found in eukaryotic cells, but they do not serve the same purpose as plasmids in genetic engineering.

• RNA molecules, while essential for many cellular functions and processes, do not define