Question

Assertion (A): Mutation selection technique identifies micro organisms that have been improved by induced mutations.
Reason (R): Mutations cannot be induced by irradiations in micro-organisms.

• A. Both Assertion (A) and Reason (R) are true and the Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but the Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

UV light ($260\text{ nm}$) is a non-ionizing radiation commonly used in laboratory research to induce point mutations in bacteria, which are then selected using diagnostic traits like antibiotic resistance or replica plating.

Answer 1

The Correct Option is C

Step 1: Evaluating the Assertion (A)
The mutation selection technique involves exposing a microbial population to a mutagen, followed by screening or plating them on selective media to identify mutant strains with improved traits (e.g., higher antibiotic production or metabolic resistance). Thus, Assertion (A) is true.

Step 2: Evaluating the Reason (R)
Mutations can be induced in microorganisms using physical mutagens, such as electromagnetic radiation (UV light, X-rays, or gamma rays), which damage DNA bases or cause covalent cross-linking (thymine dimers). The statement claiming mutations cannot be induced by irradiations is false. Thus, Reason (R) is false.

Step 3: Conclusion
Since A is true and R is false, the correct option is (C). Final Answer: (C)