What is Cas9 protein that is often mentioned in news?
A
A molecular scissors used in targeted gene editing
B
A biosensor used in the accurate detection of pathogens in patients
C
A gene that makes plants pest-resistant
D
A herbicidal substance synthesized in genetically modified crops
Correct Answer: Option A
Explanation
1. Cas9 is a protein, specifically an RNA-guided DNA endonuclease enzyme.
2. It is associated with the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) adaptive immune system in bacteria.
3. In the context of biotechnology and gene editing, Cas9 acts as precise 'molecular scissors'.
4. Guided by a specific RNA molecule (guide RNA), Cas9 cuts double-stranded DNA at a targeted location.
5. This targeted DNA cleavage enables scientists to perform targeted gene editing – inserting, deleting, or modifying genes with high precision.
6. Option (A) correctly describes this primary function. Options (B), (C), and (D) describe other unrelated biological entities or functions.