Question

What is the source of Ti plasmid used in genetic engineering?
A. Escherichia coli
B. Bacillus thuringiensis
C. Agrobacterium rhizogenes
D. Agrobacterium tumefaciens

Answer 1

Hint:It is a rod-shaped, motile gram-negative bacterium. In certain dicots, this bacterium can cause crown gall disease. This bacterium is used in the process called transformation.

Complete answer:
Genetic engineering is the tool used to change the genetic make-up of an organism by recombinant DNA technology. Humans have historically manipulated genomes with desired characteristics by checking breeding and choosing offspring indirectly. Direct modification of one or more genes is part of genetic engineering. The gene for an organism is most commonly added to the genome to give it a needed phenotype from another species.

The Ti plasmid is part of an Alphaproteobacteria plasmid family. These plasmids are mostly very large between 100kbp and 2Mbp. They are often commonly called replicons, as replication starts at one spot. Agrobacterium tumefaciens is a rod-shaped, motile gram-negative bacterium. In certain dicots, this bacterium can cause crown gall disease. The plasmid, which is known as the Ti Plasmid (the tumor inducing plasmid), occurs in the tumor-cell of Agrobacterium tumefaciens that incorporates the tumor, which induces a gene (tRNA) in the host genome resulting in the development of the gall of the crown region.

Thus, the correct answer is option D. i.e., Agrobacterium tumefaciens.

Note:Direct modification of one or more genes is part of genetic engineering. The gene for an organism is most commonly added to the genome to give it a needed phenotype from another species. Genetic engineering is the tool used to change the genetic make-up of an organism by recombinant DNA technology.