Question

The tumor inducing capacity of Agrobacterium tumefaciens is located in large extra chromosomal plasmid called as:
a) Ti- plasmid
b) Ri- plasmid
c) Lambda- phage
d) Plasmid pBR322

Answer 1

Hint: A plasmid is a short, extra chromosomal molecule of DNA inside a cell that can replicate independently and is physically isolated from chromosomal DNA. Plasmid pBR322 is used for the cloning vehicles.

Complete answer:
Agrobacterium tumefaciens is a pathogenic bacterium in soil plants that bears the plasmid Ti. It can pass to the nucleus of infected cells a specific segment of the tumor-inducing (Ti) plasmid. The transferred T-DNA is then inserted into the host genome and, causing crown gall, the cells are transformed. Agrobacterium rhizogenes is a plant pathogen causing hairy root disease due to root-inducing plasmid involvement (Ri). Ri plasmid host cell transition induces hairy roots; it does not induce tumors. Intracellular parasites that inject their genome into the bacterial cell are needed by phages, accompanied by degradation of the genetic material of the cell, replication of the viral genome, assembly of new virus particles and their release by host cell lysis. As a cloning vector for E, Plasmid pBR322 is used.

Note:
Agrobacterium tumefaciens is a plant pathogen and, as a plant genetic engineer, the most effective. In plants, it induces the development of crown gall. In gene cloning in plants, the tumor-inducing plasmid Ti can be used as a useful cloning vector. A fragment of DNA that converts normal plant cells into tumor cells is added. The Ti plasmid belongs to a plasmid genus borne by several species of Alphaproteobacteria. The existence of a conserved DNA region is described by members of this plasmid family.