What is Cas9 protein that is often mentioned in news?
Show answer
Answer: A. Cas9 is an enzyme from the CRISPR-Cas9 system that cuts DNA at a chosen spot, guided by an RNA. It works like molecular scissors for targeted gene editing.
Watch for: Students who link CRISPR to GM crops may pick a crop-related option.
Why the other options are wrong
- B. Wrong because Cas9 is not a biosensor for detecting pathogens.
- C. Wrong because Cas9 is a protein, not a pest-resistance gene in plants.
- D. Wrong because Cas9 is not a herbicide.
Source to check: Jinek et al. (2012), 'A programmable dual-RNA-guided DNA endonuclease', Science 337; NCERT Class 12 Biology, Chapter 11 'Biotechnology: Principles and Processes'
Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.