Question

Can someone explain in simple words what happens in the biogenesis step in CRISPR bacterial immunity system? I keep asking this question on chegg, but everyone keeps giving complicated answers. Can someone explain it so that is easy to understand? But please still be detailed. thanks

Answer 1

Answer-

According to the given question-

• We know that CRISPR-Cas9 is a tool used for· Genome editing or gene editing and the DNA was change by either deleting or removing some part of DNA, or inserting or adding genetic material at particular location.
• CRISPER- is called  Clustered Regularly Interspaced Short Palindromic Repeats and it have two components- one is  Cas9 also called CRISPR-associated protein 9 -which cut the DNA while other is  Guide RNA- which recognizes the sequence which need to be edited.
• In this process the genome or DNA responsible for causing health problem or disease was studied and after that a specific guide RNA was created which recognize that particular nitrogenous bases stretch of DNA.
• After that the  guide RNA binds to Cas9 which is a  DNA cutting enzyme followed by introduction of complex inside the  target cell. now this cas9 cut DNA and then we can edit the genome which depend upon need , either deleted or inserted specific sequences.  
• Bacteria can capture some part of  DNA of viruses which invading them. bacteria use the DNA of virus and make that small part of DNA segment which is known as  CRISPR arrays.now this CRISPR arrays helps in remember the closely related virus or previously invaded viruses.
• CRISPR-Cas9 presen in bacteria and these bacteria uses this tool for editing of genome when they get infected with viruses.
• After infection with viruses bacteral take small part of their genome and cmake small segment of DNA as CRISPR arrays.When becteria was again attacked by virus then CRISPR arrays of bacteria makes  RNA segments which helps in  targeting virus DNA and after that they uses  Cas9 to cut the virus DNA and neutralizes the virus.

So this play an important role in bacterial immune system.