What is the role of CRISPR-Cas in bacteria?

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Multiple Choice

What is the role of CRISPR-Cas in bacteria?

CRISPR-Cas systems in bacteria act as an adaptive immune defense. They remember past invaders by incorporating short snippets of viral DNA as spacers into the CRISPR array. When the same invader shows up again, the system uses those spacers to produce guide RNAs that recruit Cas nucleases to matching DNA sequences and cut them, thwarting infection. This memory-based, sequence-specific interference helps bacteria defend against phages and plasmids. The other options describe unrelated roles: a metabolic pathway for sugar use, a DNA repair process in eukaryotes, or a toxin–antitoxin system. CRISPR-Cas is best understood as this adaptive immune mechanism in bacteria.

CRISPR-Cas systems in bacteria act as an adaptive immune defense. They remember past invaders by incorporating short snippets of viral DNA as spacers into the CRISPR array. When the same invader shows up again, the system uses those spacers to produce guide RNAs that recruit Cas nucleases to matching DNA sequences and cut them, thwarting infection. This memory-based, sequence-specific interference helps bacteria defend against phages and plasmids. The other options describe unrelated roles: a metabolic pathway for sugar use, a DNA repair process in eukaryotes, or a toxin–antitoxin system. CRISPR-Cas is best understood as this adaptive immune mechanism in bacteria.

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