Question

Arrange the following steps in recombinant DNA technology on the basis of their sequence of occurrence:
(A) Isolation of desired DNA fragments
(B) Culturing the host cells
(C) Extraction of desired product
(D) Ligation of DNA fragment into vector
(E) Transferring of recombinant DNA to host
Choose the correct answer from the options given below:

• A. (A), (E), (C), (B), (D)
• B. (A), (D), (E), (B), (C)
• C. (B), (C), (A), (D), (E)
• D. (B), (A), (D), (C), (E)

Answer 1

The Correct Option is B

In recombinant DNA technology, the following sequence is used to successfully manipulate and utilize DNA fragments:

1. Isolation of desired DNA fragments (A): This is the first step where specific segments of DNA are extracted from the donor organism, ensuring the required gene of interest is obtained.
2. Ligation of DNA fragment into vector (D): The isolated DNA fragments are then inserted into a cloning vector, which acts as a vehicle to carry the gene into host cells.
3. Transferring of recombinant DNA to host (E): The vector with the desired DNA is introduced into a host cell, facilitating the propagation and expression of the recombinant DNA.
4. Culturing the host cells (B): The host cells containing the recombinant DNA are cultured and multiplied, allowing the genetic material to be maintained and amplified.
5. Extraction of desired product (C): Finally, the desired product, usually a protein or other biochemical, is extracted from the cultured host cells for further use or study. 

In summary, these steps should be executed in the following order: (A), (D), (E), (B), (C).

Answer 2

Let's arrange the steps of recombinant DNA technology in the correct sequence:

(A) Isolation of desired DNA fragments: The first step involves isolating the specific DNA fragment that contains the gene of interest. This is done by using restriction enzymes to cut the DNA at specific locations.

(D) Ligation of DNA fragment into vector: The isolated DNA fragment is then inserted into a vector, such as a plasmid, using the process of ligation (using the enzyme ligase). This forms a recombinant DNA molecule.

(E) Transferring of recombinant DNA to host: The recombinant DNA is introduced into a host cell (like an E. coli bacterium) through methods like transformation, making it capable of replicating the recombinant DNA.

(B) Culturing the host cells: The host cells, now containing the recombinant DNA, are cultured in a suitable medium. This allows the host cells to multiply and replicate the recombinant DNA.

(C) Extraction of desired product: After culturing, the desired product (such as a protein) is extracted from the cultured cells, completing the process.

Thus, the correct sequence is:

(A) Isolation of desired DNA fragments, (D) Ligation of DNA fragment into vector, (E) Transferring of recombinant DNA to host, (B) Culturing the host cells, and (C) Extraction of desired product.

The correct answer is (2) (A), (D), (E), (B), (C).