Advanced questions
12. When the Cas9 nuclease cuts DNA, the cell often introduces mutations as
the cell's repair mechanisms work to fix the break. Explain why mutations
that inactivate a gene may be useful to scientists.
Type your answer here.
13. In this lab, you added the Cas9 nuclease to the DNA sample in a test tube.
When scientists want to use CRISPR/Cas9 in living cells, one common
method is to introduce the cas9 gene and allow the cell to produce the
Cas9 protein itself. Cas9 is a protein normally found in bacteria. But
scientists can use the cells of any organism to produce Cas9. Discuss how
this relates to the concept of a universal genetic code.
Type your answer here.
Using mathematical thinking
14. Let's assume we have a restriction enzyme that targets the six-base
sequence CGATCG.
● What are the chances of this specific six-base DNA sequence
matching any random six-base-pair stretch of DNA?
● You should use a calculator, but show your work.
Type your answer here.
15. Let's use our gRNA1, which targets the 20-base sequence
GCTAGTCATGCTACCCTAGT.
● What are the chances of this specific 20-base DNA sequence
matching any random 20-base-pair stretch of DNA?
● You should use a calculator but show your work.
Type your answer here.
16. Again, let's assume we have a restriction enzyme that targets the 6-base
sequence CGATCG.
● How many times could you expect this restriction enzyme to find
and cut the CGATCG sequence in the 3.2 billion (3,200,000,000)
base-pair long human genome?
● You should use a calculator but show your work.
Type your answer here.
Chopped! Using CRISPR/Cas9 to cut DNA Lab. Student E-worksheet™.
Release: September 2023. © 2023 by miniPCR bio
TM
