NEET BIOLOGY

Detailed explanation-1: -Correct option a fragment of DNA which acts as vector Explanation:A plasmid is a piece of DNA mostly in bacteria but also in yeast not forming a part of normal chromosomal DNA of a cell but capable of replicating independently of it. These often act as vehicles for gene transfer.

Detailed explanation-2: -Plasmids can be used as tools to transfer, clone and manipulate genes. Those plasmids that are used experimentally for such purposes are called vectors. Into plasmid vectors, DNA fragments or genes can be inserted to create a “recombinant plasmid”.

Detailed explanation-3: -Scientists have taken advantage of plasmids to use them as tools to clone, transfer, and manipulate genes. Plasmids that are used experimentally for these purposes are called vectors. Researchers can insert DNA fragments or genes into a plasmid vector, creating a so-called recombinant plasmid.

Detailed explanation-4: -Plasmid DNA (pDNA) is the base for promising DNA vaccines and gene therapies against many infectious, acquired, and genetic diseases, including HIV-AIDS, Ebola, Malaria, and different types of cancer, enteric pathogens, and influenza.

Detailed explanation-5: -With regards to structure, plasmids are made up of circular double chains of DNA. The circular structure of plasmids is made possible by the two ends of the double strands being joined by covalent bonds.