Genetic Engineering

Question 1

What is genetic engineering

Answer 1

The manipulation of an organism’s DNA
These transformed organisms have recombinant DNA - DNA formed by joining together from different sources

It involves extracting a gene from one organism and then inserting it into another organism

An organism that carries a gene from another organism is termed ‘transgenic’ , GMO

Question 2

First part of genetic engineering
2 ways to isolate desired gene?

Answer 2

Isolate the DNA fragment that contains the derived gene using restriction enzymes (restriction endonucelases)
Restriction enzymes used to cut the required gene from the DNA
The sticky ends make it easier to insert the desired gene into the DNA of a different organism

Another way involves isolating the mRNA for the desired gene and using the enzyme reverse transcriptase to produce a single strand of complementary DNA.
The advantage of this technique is that it makes it easier to identify the desired gene

Question 3

Second part

Answer 3

Insert the the DNA fragment into vector DNA (a vector is something used to transfer DNA into a cell)
Vectors can be plasmids or bacteriophages

1) vector DNA is isolated
2) the vector DNA is cut open using the same restriction enzyme that was used to isolate the DNA fragment contained the desired gene
This means the sticky ends of the vector DNA (plasmid) are complementary to the sticky ends of the DNA fragment contained the gene
3) the vector DNA and DNA fragment are mixed together with DNA ligase. DNA ligase joins the sugar phosphate backbones of the two bits of DNA. This process is called ligation
4) the new combination of bases in the DNA (vector DNA + complementary DNA) is called recombinant DNA

Question 4

part 3
What is electroporation?

Answer 4

The vector with the recombinant DNA is used to transfer the gene into the bacterial cells (host cells)

Electroporation:
A suspension of the bacterial cells is mixed with the plasmid vector and placed in a machine called an electroporator. Machine switched on (electrical field) increases permeability of bacteria cell membranes and allows them to take in the plasmids.