3.5 Study Guide Flashcards
What is the function of the CRISPR system in bacteria
a. Sensing of metabolites
b. Adaptive immune response
c. Antibiotic resistance
d. Engineering the genome of other organisms
e. All of the above
Adaptive immune response
In a CRISPR array what is the spacer?
a. a palindromic repeat that separates the foreign DNA regions
b. The gene encoding the tracrRNA
c. A nuclease enzyme
d. A piece of foreign DNA integrated into the bacterial genome
e. None of the above
A piece of foreign DNA integrated into the bacterial genome
Which enzyme integrates foreign DNA into the bacterial genome?
a. Cas9
b. crRNA
c. PAM
d. Cas1/Cas2
e. tracrRNA
Cas1/Cas2
What is the function of PAMs
a. They are nucleotide sequences that cause non-host DNA to be recognized
b. They inhibit activity of Cas9
c. They provide a structural scaffold for crRNAs
d. They are catalytic domains that degrade DNA
e. They allow viruses to kill bacteria
They are nucleotide sequences that cause non-host DNA to be recognized
Which is NOT a phase of CRISPR function in bacteria
a. Integration of non-self DNA into the host genome
b. Production of crRNAs from CRISPR arrays
c. RNA-directed cleavage of foreign DNA
d. All of these are phases of CRISPR function
All of these are phases of CRISPR function
What directs the precise location where foreign DNA inserts into the bacterial host genome?
a. PAM
b. The leader sequence
c. The repeat sequence
d. The spacer sequence
e. Foreign DNA can insert anywhere
The leader sequence
What is the specific function of the repeat region in a crRNA transcribed from a CRISPR array?
a. It is complementary to foreign DNA
b. It base pairs with the tracrRNA
c. It inhibits Cas9 activity
d. It degrades foreign DNA
e. There is no repeat region in crRNA
It base pairs with the tracrRNA
To degrade foreign DNA, three components are needed in the complex. One is cas9, another is
tracrRNA. What is the third component of the complex that degrades foreign DNA?
a. IHF
b. Cas1
c. Cas2
d. crRNA
e. PAM
crRNA
Cas9 protein has two lobes - the nuclease lobe and:
a. The recognition lobe
b. The integrase lobe
c. The recombination lobe
d. The nickase lobe
e. The integrated host factor lobe
The recognition lobe
How is Cas9 activated to search for and identify target DNA for cleavage?
a. Migration to the nucleus
b. Conformational change due to binding the crRNA/tracrRNA complex
c. Self-processing using its nuclease activity
d. Cas9 is always active
e. Cas9 is not the component that identifies target DNA for cleavage
Conformational change due to binding the crRNA/tracrRNA complex
A DNA strand has a PAM site but the 20 nucleotides adjacent to it are not complementary to the
crRNA. What happens to this DNA?
a. Cas9 very rapidly dissociates from the DNA
b. Cas9 unwinds the DNA a little bit, but moves on once the DNA fails to base pair with the crRNA
c. The DNA base pairs with the crRNA but is not cut by Cas9
d. The PAM site is all that is required for Cas9 to cut DNA
Cas9 unwinds the DNA a little bit, but moves on once the DNA fails to base pair with the crRNA
Why is Cas9 so commonly used for genome editing?
a. It doesn’t require an RNA template
b. It cuts viral DNA
c. It contains all necessary enzyme activities in a single protein
d. All of the above
e. Cas9 is NOT commonly used for gene editing
It contains all necessary enzyme activities in a single protein
Synthetic single guide RNAs (sgRNAs or gRNAs) are a fusion of a crRNA with another element. Which
is the other element?
a. PAM sequence
b. Cas9
c. Viral DNA
d. tracrRNA
e. Host DNA
tracrRNA
When using CRISPR/Cas9 for genome editing, which mechanism repairs the double-stranded break
to commonly cause small insertions or deletions at the cleavage site?
a. Homology-directed recombination
b. Spacer insertion by Cas1/Cas2
c. Non-homologous end-joining
d. Ligation by Cas9
e. Any of the above
Non-homologous end-joining
How do you generate dCas9?
a. By eliminating nuclease activity of the Cas9 RuvC site
b. By eliminating nuclease activity of the Cas9 HNH site
c. By eliminating activity of both the RuvC and HNH sites in Cas9
d. By eliminating interaction of Cas9 with the sgRNA
e. By eliminating the ability of Cas9 to bind DNA
By eliminating activity of both the RuvC and HNH sites in Cas9
