Question

Assertion: Ti plasmids are used to transfer genes to the host cells
Reason: They are natural vectors which deliver genes to the eukaryotic cells

• A. Both the assertion and reason are true and the reason is the correct explanation of assertion
• B. Both the assertion and reason are true but the reason is not the correct explanation of assertion
• C. Assertion is true but the reason is false
• D. Both the assertion and reason are false

Answer 1

The correct option is A Both the assertion and reason are true and the reason is the correct explanation of assertion

Tumour inducing plasmid (Ti) is present in Agrobacterium tumefaciens which is a pathogen of several dicot plants.

This bacterium naturally delivers its “T-DNA” (part of Ti plasmid) to the host. This leads to transformation of normal plant cells into tumour cells which causes them to produce chemicals required by the bacterial pathogen.

The Ti plasmid has now been modified into a cloning vector which is no more pathogenic to the plants but is still able to deliver genes of our interest into a variety of plants.

So, we can conclude that Ti plasmid is a natural vector of eukaryotic plant cells. This property has been used to transfer desired genes into the host cell.

Hence, both the assertion and reason are true and the reason is the correct explanation of assertion.