Question

Given below are two statements :
one is labelled as
Assertion (A) and the other is labelled as
Reason (R).
Assertion (A) :
E.coli is widely used as a host in RDT.
Reason (R) :
E.coli grows rapidly and its genetics are well understoo
D.
In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Remember why E.coli is preferred in RDT:
• Rapid growth
• Easy genetic manipulation
• Availability of plasmids
• Cost-effective cultivation \[ \textit{E.coli} = \text{Most widely used bacterial host in molecular cloning} \]

Answer 1

The Correct Option is A

Concept: Recombinant DNA Technology (RDT) involves insertion and expression of foreign genes in suitable host organisms. Escherichia coli (E.coli) is one of the most commonly used host organisms in molecular biology because it possesses several advantages:
• Rapid growth rate
• Easy cultivation
• Simple nutritional requirements
• Well understood genetics
• Availability of numerous cloning vectors These characteristics make E.coli highly suitable for gene cloning and recombinant protein production.

Step 1: Evaluating Assertion (A). The assertion states: \[ \textit{E.coli} \text{ is widely used as a host in RDT} \] This statement is correct because E.coli is extensively used in:
• Gene cloning
• Recombinant protein production
• Plasmid amplification Therefore: \[ \boxed{(A) \text{ is correct}} \]

Step 2: Evaluating Reason (R). The reason states: \[ \textit{E.coli} \text{ grows rapidly and its genetics are well understood} \] This statement is also correct. E.coli has:
• Short generation time
• Easily manipulable genome
• Extensive genetic information available Hence: \[ \boxed{(R) \text{ is correct}} \]

Step 3: Determining whether (R) explains (A). The reason directly explains why E.coli is widely used in recombinant DNA technology. Because: \[ \text{Rapid growth + Well understood genetics} \] make it highly convenient as a host organism. Thus: \[ \boxed{(R) \text{ correctly explains } (A)} \] Therefore, the correct answer is: \[ \boxed{(A)\ \text{Both (A) and (R) are correct and (R) is the correct explanation of (A)}} \]