During the CRISPR process, what happens in the 'Extermination' step?

In the 'Extermination' step of the CRISPR process, the correct action involves the Cas9 complex binding to the target DNA and cutting it. This is a critical function of the CRISPR-Cas9 technology, which is a part of the bacterial immune system that protects against invading phages (viruses that infect bacteria).

During this step, the Cas9 protein utilizes a guide RNA to precisely locate the specific sequence of invading viral DNA. Once the binding occurs, Cas9 introduces double-strand breaks in the DNA at targeted sites. This cutting action effectively disables the viral genome, preventing the virus from replicating and further infecting the bacterial cell. The specificity of the process allows bacteria to effectively recognize and defend against previously encountered viruses, enhancing their survival.

This understanding underlines why the other choices do not accurately describe the 'Extermination' step. The adaptation of bacterial cells or the production of more viral DNA does not occur during this phase; instead, the focus is on the destruction of foreign genetic material through targeted cutting. Similarly, transcribing RNA from viral DNA is part of other processes that occur prior to the Extermination step, such as the adaptation or maturation phases of the CRISPR immune response.