Genetic engineering

What is genetic engineering?

the direct manipulation of DNA to alter an organism’s characteristics in a specific way

What are the seven steps to genetically engineer a bacetrium to synthesize a foreign gene product

1. Purify the plasmid

2. Make many copies of the target DNA (insert)

3. Use restriction enzymes to cut the insert and the plasmid

4. Ligate the cut insert into cut plasmid using DNA ligase

5. Transform the cells with the recombinant plasmid

6. Induce expression of the gene

7. Purify the product

What is a cloning vector

a small piece of DNA that can be stably maintained by a recipient organism and used to transmit genes from one organism to another

what are vectors’ key properties?

• An origin of replication

• a selectable marker, such as an antibiotic resistance gene

• Restriction enzyme cut sites

  • high copy number and small size

What are restriction enzyme?

endonucleases that cut the phosphate-sugar backbone of double-stranded DNA at specific recognition sequences

How do bacteria protect themselves from viruses using a restriction-modification (R-M) system

the system consists of a restriction enzyme and a methylase;

- the RE cuts viral DNA that contains a specific recognition sequence which prevents the virus from replicating

• The methylase modifies the hosts DNA by adding a methyl group to the same recognition sequences, which prevents the RE from cutting the host DNA

What is the purpose of Polymerase Chain Reaction (PCR)

its used to amplify or make many copies of a specific DNA sequence through in vitro DNA replication

What are the main components of a PCR reaction?

• water

• buffer

• dNTP

• heat stable DNAP

• MGCL2

• Primers

• DNA Template

How does the CRISPR-Cas system protect bacteria from bacteriophage infection?

It acts as an immune system, it works by incorporating pieces of foreign viral DNA into a CRISPR array on the chromosome