Ch 2.5 CRISPR

Question 1

What does CRISPR stand for?

Answer 1

Clustered Regularly Interspaced Short Palindromic Repeats

Question 2

What does CRISPR do?

2

Answer 2

• Easy/precise gene editing

- can study gene function/ potential cures

Question 3

Where was CRISPR discovered?

Answer 3

• bac immune system against bacteria phages

- bac produces CRISPR-Cas9 find phage dna and cut it out

Question 4

Palindromic sequences:

Answer 4

Sequence on dna/rna where 5-3 forward on one strand matches sequence reading 5-3 on complementary strand

Question 5

CRI in CRISPR

Answer 5

• refer palindromic repeats found cluster area of bac genome
• repeats spaced apart regularly intervals

Question 6

Spacer dna:

Answer 6

Dna filled spaces between palindromic repeats

All unique and matched perfectly to dna found in the phages

Question 7

CAS genes:

Answer 7

Crispr Associated gene

Provide genetic instructions for building Cas proteins

Cas proteins usually made helicase enzyme and nuclease enzymes (cuts dna)

Question 8

Guide RNA

Answer 8

Cas gene transcribed/ translated to cas protein with ability unwind/cut invader dna

CRISPR dna transcribed to segments guide rna

Each segment guide rna each compliment to one segment spacer dna and one palindromic repeat

Question 9

What do cas and gRNA combine to form

Answer 9

CRISPR-CAS9 complex

Question 10

How does Cas9 work

Answer 10

Unwind dna so gRNA can bind to it’s complimentary segment of viral dna

Cas9 cuts viral dna to inactivate it

Question 11

What are the 3 stages of CRISPR defense mechanism

Answer 11

1) Adaption: insertion new spacers
2) expression: expression cas genes, transcribe CRISPR to guide RNA by CAS proteins and accessory factors
3) interference: recognize and destroy target nucleus acid