Question

Arrange the following in sequential order of their usage in recombinant DNA technology.
I) Calcium chloride
II) DNA ligase
III) Ethylenediaminetetraacetic acid
IV) Restriction endonuclease

A. (I), (IV), (III), (II)
B. (IV), (I), (II), (III)
C. (I), (IV), (II), (III)
D. (III), (IV), (II), (I)

Answer 1

Recombinant DNA technology involved in the manipulation in DNA molecules (target gene/DNA) to achieve the desired goal. It is done by selecting and extracting the target DNA molecules, followed by the cutting and joining with the vector. Finally, the recombinant DNA is transferred into a host cell for the multiplication of target gene/DNA.

Complete answer:
The process of recombinant DNA technology involves several steps, they are as follows:

Extraction or Isolation of genetic material (DNA or RNA): Extraction of DNA molecules can be done by using two methods that are, by lysing the cell gently in a buffer and solubilise the DNA. The most common buffer used is the Tris-EDTA buffer. It helps in dissolving the DNA or RNA and also protects the genetic material from degradation.
Cutting of specific DNA fragments: the enzyme called restriction endonucleases are used to cut the specific DNA sequence, called target DNA or gene of interest. The same enzyme is used to cut the vector.
Ligation of DNA molecules: In this step, the target DNA fragment and vector molecules are joined together with the help of an enzyme called ligase. The resultant DNA molecule is called recombinant DNA.
Amplification of gene of interest: The gene of interest gets amplified by using the technique called a polymerase chain reaction. In this technique, a single or few numbers of DNA amplify into millions of copies or numbers.
Insertion of recombinant DNA (rDNA) into the host cell: This step is done for the multiplication of the target gene or DNA. Before inserting the rDNA into the host cell, the host cell makes it competent so that it can easily accept the rDNA molecules. This is done by treating the host cell with a specific concentration of divalent cation such as calcium chloride.

Hence from the above discussion, the correct answer is option D that is (III), (IV), (II), (I).

Note: Recombinant DNA technology has many applications such as in agriculture, medicine, production of the vaccine, gene therapy, bioremediation and also in waste management technique, and energy production.