Question

Plasmids are
A)Viruses
B)Extrachromosomal genetic element of bacteria
C)New type of microorganism
D)Genetic element of bacteria

Answer 1

A plasmid is a thin, double-stranded, circular DNA molecule that is distinct from the chromosomal DNA of a cell. In a plasmid vector, researchers may insert DNA fragments or genes, producing a so-called recombinant plasmid. By means of a mechanism called transformation, this plasmid may be inserted into a bacterium.

Complete answer:
A plasmid is a small molecule of DNA inside a cell that is isolated from a chromosomal DNA physically and can replicate independently. In bacteria, they are most frequently present as thin, spherical, double-stranded DNA molecules. Just a few genes are borne by plasmids and occur independently of chromosomes, the primary structures supplying DNA in cells. Plasmids, capable of self-replicating, can be obtained from the atmosphere and passed between bacteria. To cope with stress-related conditions, plasmids are used by their host organism.

The production of molecular biotechnology has been driven by plasmids. To inject foreign DNA into bacteria, they serve as transmission vessels, or vectors. In the 1970s, when DNA from other species was first 'cut and pasted' onto unique locations within the plasmid DNA, the use of plasmids for DNA distribution began.

Hence, the correct answer is option (B)

Note: Plasmids have multiple functions that are distinct. They can contain genes that boost an organism's survival, either by destroying other organisms or by creating toxins to protect the host cell. The mechanism of replication in bacteria is facilitated by certain plasmids.