Question

Identify correct combinations.

List I	List II	List III
A) PCR	i) Specific base sequence	I) Taq polymerase
B) Downstream processing	ii) Inheritable gene	II) Ampicillin
C) Restriction endonuclease	iii) Amplification of DNA	III) EcoRI
D) Selectable marker	iv) Transformation and non-transformation v) Product separation and purification	IV) Quality control V) Ori

• A. A- iii- I, B- v- IV, C- ii- V, D-i- III
• B. A- ii- IV, B- iv- I, C- ii- V, D-iii- I
• C. A- iii- I, B- v- IV, C- i- III, D-iv- II
• D. A- iii- I, B- iv- I, C- i- III, D-ii- V

Answer 1

Answer: (C)

• PCR (Polymerase Chain Reaction) is the process of amplification of the DNA. The enzyme Taq polymerase is the enzyme that is used to add the nucleotides to the copies of new DNA which are synthesized. The enzyme is stable at various temperatures and does not gets denatured when the PCR is carried out at different temperatures in different stages.
• Downstream processing involves the various steps which are carried out to separate the product and then purify. This step is performed when the product is obtained in the crude form. These are the steps that are important with respect to quality control.
• Restriction endonuclease is the enzymes that are used for the cleavage of the DNA at specific sites. There is a recognition site at which there is a specific base sequence that allows cleavage at the proper site. EcoRI is the restriction enzyme that is isolated from E.coli.
• Selectable markers are the specific genes that are used to identify the transformants and the non-transformants after the process of recombination. The ampicillin gene is commonly used as a selectable marker.

Thus, the correct answer is option C.