CRISPR/Cas

Question 1

CRISPR (Cluster Regularly Interspaced Short Palindromic Repeats)

Answer 1

• regions in prokaryotic genomes that provide defence against viral infections, similar to vertebrates’ immune system in that they are responsive and heritable

Question 2

Mechanism

Answer 2

A phage infects a bacterium, and regions of the phage’s DNA are clipped, replicated and integrated into a new CRISPR locus, separated by spacers. Transcription of the region produces CRISPR RNAs (crRNA) that bind to the Cas protein. The Cas protein uses the bound RNA as a probe, When a match to the region of DNA from the invading virus is detected, the Cas protein will clip the viral DNA, the degradation of the viral DNA is the defence mechanism of the cell.

Question 3

Application

Answer 3

Gene knockout- is silencing gene expression
Gene editing- is replacing/inserting DNA sequences into endogenous genes
Gene drive- using CRISPR/Cas to accelerate the dispersal of a chosen gene throughout the population