Question

Please help me answering these multiple questions of how the CRISPR system works, thank you!

1. Match the CRISPR component with its function. (matching the upper case letters to the lower case letters)
A). Cas9
B). gRNA (sometimes called sgRNA)
C). Non-homologous End Joining (NHEJ)
D). Homology-directed Repair (HDR)

a). A short RNA molecule that guides a DNA cutting enzyme to a specific location in genomic DNA.

b). A type of DNA repair mediated by a set of enzymes all cells contain that introduces small insertions or deletions into the repaired region.

c). Enyzme that creates a double-stranded DNA break.

d). A type of DNA repair mediated by a set of enzymes all cells contain that uses "template" DNA to mediate repair of the damaged region. The "template" DNA has a very sequence to the repaired region.

2. Why is the CRISPR system so powerful? Check all that apply.

a). It has very high fidelity (it finds and changes the target sequence with few mistakes).

b). It is programmable to target any sequence of DNA.

c). The proteins cause cells in which the DNA has been altered to fluoresce (glow).

d). It is functional across all species of organism.

3. The CRISPR system was discovered in bacteria. What purpose did it serve in those cells?

a). It keeps a genetic record of viruses a bacterial cell has been exposed to and will protect the bacterial cell from future infections by those viruses.

b). The CRISPR system is a weapon that certain species of bacterial cells use against other bacterial cells to "protect" areas rich in resources.

c). The CRISPR system is a signaling system that will recruit various bacterial species into biofilms.

d). When environmental conditions change, the CRISPR system triggers alterations to the genome in order to adapt to the new environment.  

Answer 1