BIOL 330 Study Guide - Final Guide: Repressor, Ribonuclease Iii, Crispr

• School: Queen's University
• Department: Biology
• Course: BIOL 330
• Professor: Sharon Regan

Document Summary

Crispr cas9 = genome editing system (changes to the nucleotide sequence of the genome: crispr (clustered regularly interspaced short palindromic repeats)- a defense mechanism in bacteria that detects foreign virus dna and destroys it. Uses a guide rna sequence to target (through complementary base-pairing) double-stranded dna, which it then cleaves: cas9- a protein part of the crispr system able to detect and degrade foreign dna. When bacteria are first infected by a virus, they have a mechanism that causes short fragments of that viral dna to become integrated into their genomes. These serve as vaccinations as they become the templates for producing small noncoding crrnas (crispr rnas) that will thereafter destroy the virus should it re-infect the descendants of the original cell. These crrnas then become associated with special proteins that allow them to seek out and destroy double-stranded dna molecules, rather than single-stranded rna molecules.