(1.) which question below do scientists need to answer, to determine whether CRISPR can be used to fight a new bacterium that is resistant to antibiotics?

A. Where did the bacterium come from?
B. What sequence of nucleotides does the guide RNA need to include, to kill the bacterium?
C. What proteins do the virus’s guide RNA code for?

(2.) Which of the following system components is likely to be direct (immediate) cause the antibiotic-resistant bacterium’s own DNA to be destroyed?

A. the invasion of the bacteriophage (virus) into the bacterium
B. the action of the Cas-9 protein
C. the production of the Cas-9 protein
D. the coding of the guide RNA

1. B

2. B

Explanation:

CRISPR/Cas9 is usually used as a way to edit genes. The Cas9 protein can make cuts in the DNA (think of it like molecular scissors). Scientists provide a guide RNA to direct the cutting action of the Cas9 protein to particular parts of the genome, allowing them to edit genes.

In terms of antibiotic resistance, scientists could target the antibiotic resistance genes of the bacteria, meaning they will no longer be resistant.

1. For CRISPR to be effective, scientists need to design guide RNAs that specifically target a gene of interest that they want to edit. In this case, scientists need to know what gene gives the bacteria resistance, so that they can chop it out with Cas9. To design the guide RNAs against the gene, they have to know the nucleotide sequence of the gene, to design a complementary guide RNA.

2. The Cas9 protein is like molecular scissors. The guide RNA finds its complementary DNA sequence, bringing he Cas9 to that region and causing it to chop that DNA, thereby destroying the bacteria's DNA. Therefore, this relies on the action of the Cas9 protein

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