Why is screening not necessary to select for microbes that have been edited using the Cas9 system? Multiple Choice The Cas9 system converts mutant cells to wild-type, which will grow on any media whereas the mutants will not

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Why is screening not necessary to select for microbes that have been edited using the Cas9 system?

Multiple Choice

• The Cas9 system converts mutant cells to wild-type, which will grow on any media whereas the mutants will not.

• The activated CRISPR sequence targets lysogenic bacteriophages, which kills the cells.

• The edited microbes include green fluorescent protein which eliminates the need to grow the cells on a plate containing antibiotic.

• Microbes that have not repaired the cut by insertion of donor DNA cannot carry out nonhomologous end joining and chromosome breaks are lethal.  

Why is important to construct the donor DNA using seamless cloning techniques?

 

 

Multiple Choice

• The ends of the donor DNA must be homologous to the sequences flanking the break in the chromosome for recombination to occur.

• The Cas9 nuclease can only recognize regions of homology between the donor DNA and the chromosome to be edited.

• The 5' and 3' ends of the donor construct must be palindromes so they can circularize.

• The 3' end of the donor DNA must encode a recognition sequence for a restriction enzyme so that a sticky end can be created.

 

What feature of Cas9 enables genomic editing with extreme specificity?

 

 

Multiple Choice

• Once a phosphodiester bond has been hydrolyzed, targeted DNA can be inserted.

• Cas9 requires a guide RNA that can be homologous to a unique 20 base pair sequence on the target DNA.

• Cas9 recognizes and binds to a 4-8 base pair palindromic sequence and creates sticky ends following hydrolysis.

• The CRISPR guide RNA targets eukaryotic sequences allowing a specific construct to be inserted.

 

The green fluorescent protein is produced in nature by a _________ species.

 

 

Multiple Choice

• fluorescent fungus

• firefly

• jellyfish

• fluorescent bacterium