Intro genetic engineering - lecture 12

Question 1

What are restriction enzymes?

Answer 1

Cut phosphodiester bonds in DNA at specific sequences

Question 2

Why do bacteria produce restriction enzymes?

Answer 2

To combat phage infection

Question 3

EcoRv nuclease vs EcoRV methylase

Answer 3

EcoRv methylate is an enzyme which adds methyl groups to specific sequences , which prevents EcoRv nuclease form cutting there

Question 4

DNA ligase

Answer 4

catalyse the formation of phospodiester bonds between a 3’ hydroxyl and a 5’ phosphate group

Question 5

What are DNA vectors?

Answer 5

Units that can be used to store, replicate and manipulate genetic info . Plasmids are commonly used.

Question 6

What are expression vectors

Answer 6

Have a promoter near a multiple cloning site

Question 7

How do you get a gene of interest into a plasmid/

Answer 7

• Restriction enzymes at end of gene

- Design PCR primer to have restriction enzymes at the end

Question 8

what is the purpose of site directed mutagenesis?

Answer 8

Used to introduce specific changes within. the DNA sequence

Question 9

How does site - directed mutagenesis occur?

Answer 9

• methylated template plasmid to start with
• Do PCR and you get a plasmid with no methylation
• Dnp1 restriction enzyme degrades methylated temple plasmid
• left with vector with mutation

Question 10

The Cre- Loxp system

Answer 10

• Use of the Cyclization recombinase (cre) enzyme produced by bacteriophages
• Cre recognises Loxp sequences and induces a deleted sequence then recombination

Question 11

What is Crispr - Casp?

Answer 11

• A cellular systems which exists in bacteria to combat viruses
• components have been humanised to edit human genomes

Question 12

What does Palindromic mean?

Answer 12

n genetics, a DNA or RNA sequence that reads the same in both directions. The sites of many restriction enzymes that cut (restrict) DNA are palindromes.

Question 13

What organism uses the Cre-Lox P system?

Answer 13

bacteriophages