Read the given statements and select the correct optionStatement 1: Ti...
Ti plasmid (tumour inducing) from the soil bacterium agrobacterium tumefaciens is effectively used as vector for gene transfer to plant cells. this bacterium induces tumors in broad leaf plants such as tomato, tobacco and soybean.
The plasmid is "disarmed" by deletion of the tumour inducing genes. These transformed bacteria can still infect plant cells. The part of Ti plasmid transferred into plant cell DNA, is called T-DNA. This T-DNA with desired DNA spliced into it, is inserted into the chromosomes of the host plant where it produces copies of itself by migrating from one chromosomal position to another at random, but it no longer produces tumors.
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Read the given statements and select the correct optionStatement 1: Ti...
Statement 1: Ti plasmid obtained from Agrobacterium tumefaciens is effectively used as a vector for gene transfer in plant cells.
Statement 2: The part of Ti plasmid transferred into the DNA of plant cells is called as T-DNA.
Correct answer: Both statements 1 and 2 are correct, but statement 2 is not the correct explanation of statement 1.
Explanation:
Introduction:
Agrobacterium tumefaciens is a soil bacterium that is capable of transferring a part of its plasmid, known as the Ti (tumor-inducing) plasmid, into the plant cells. This transfer of genetic material allows the bacterium to genetically modify the plant cells and induce the formation of crown gall tumors, which provide a favorable environment for the growth of the bacterium.
Statement 1: Ti plasmid obtained from Agrobacterium tumefaciens is effectively used as a vector for gene transfer in plant cells.
- The Ti plasmid is commonly used as a vector for gene transfer in plant cells due to its ability to integrate its DNA into the plant genome.
- It contains several essential elements for efficient gene transfer, such as the T-DNA region, virulence genes, and an origin of replication.
- The T-DNA region is responsible for the transfer and integration of genetic material into the plant genome.
- The virulence genes present in the Ti plasmid help in the transfer process by facilitating the formation of a transfer DNA (T-DNA) complex and its transfer into the plant cells.
- The Ti plasmid has been successfully used to introduce various desirable traits into plants, such as resistance to pests, diseases, and herbicides, as well as improved nutritional content.
Statement 2: The part of Ti plasmid transferred into the DNA of plant cells is called as T-DNA.
- The T-DNA region of the Ti plasmid is the specific segment that is transferred into the plant genome during the infection process.
- It carries the genes of interest that are desired to be introduced into the plant cells.
- The T-DNA is flanked by specific DNA sequences called "border sequences" that are recognized by the virulence proteins of Agrobacterium tumefaciens.
- These border sequences act as the site of cleavage and transfer of the T-DNA into the plant cells.
- Once inside the plant cells, the T-DNA integrates into the plant genome, leading to stable inheritance of the introduced genes.
Explanation of the answer:
Both statements 1 and 2 are correct, as the Ti plasmid is indeed used as a vector for gene transfer in plant cells, and the part of the Ti plasmid transferred into the plant cells is called the T-DNA. However, statement 2 is not the correct explanation of statement 1 because it only provides additional information about the T-DNA region without directly explaining why the Ti plasmid is effectively used as a vector for gene transfer in plant cells. The effectiveness of the Ti plasmid as a vector is due to its ability to transfer the T-DNA region into the plant genome and integrate it stably.
Hence, the correct answer is option B, which states that both statements 1 and 2
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