The protein Cas9, frequently mentioned alongside CRISPR in recent news, is best described as which of the following?

Question

Accepted Answer

A. A protein that acts as molecular scissors, cutting DNA at a specific targeted location to enable gene editing. Cas9 functions as a molecular scissors within the CRISPR Cas9 gene editing system, cutting DNA at a precise location specified by a guide RNA sequence, which allows scientists to remove, insert or modify a targeted stretch of genetic material. It is not a plant hormone, an antibiotic degrading enzyme, or a diagnostic marker restricted to viral infections, which rules out the other options. Hence option A correctly describes what Cas9 actually is.

Answer

A. A protein that acts as molecular scissors, cutting DNA at a specific targeted location to enable gene editing

Answer

B. A synthetic hormone used to regulate plant growth in genetically modified crops

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C. An enzyme that breaks down antibiotics inside bacterial cells

Answer

D. A protein marker used exclusively to diagnose viral infections