NEETZoologyBiotechnology - Principles and Processes
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The Ti plasmid of Agrobacterium tumefaciens must be 'disarmed' before it can be used as a cloning vector for delivering genes into plant cells. Reason (R): The wild-type Ti plasmid is pathogenic and causes crown gall disease by integrating its T-DNA to direct the plant cell to produce chemicals for
Options
- ABoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- BBoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- CAssertion (A) is true but Reason (R) is false.
- DAssertion (A) is false but Reason (R) is true.
Correct answer
B. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Step-by-step solution
Agrobacterium tumefaciens is a pathogen of several dicot plants. It delivers a piece of DNA known as T-DNA to transform normal plant cells into a tumor (crown gall) and directs these tumor cells to produce the chemicals required by the pathogen. To use the Ti (tumor-inducing) plasmid as a cloning vector, it must be modified or 'disarmed' so that it no longer causes disease but is still able to use its mechanisms to deliver the gene of interest into the plant. Therefore, both Assertion (A) and Reason (R) are true, a