B6- Gene Technologies

What is genetic engineering?

Taking a copy of a gene from one organism and inserting that gene into the DNA of another organism, to create a genetically modified organism (GMO) or a transgenic organism

What were the first GMOs?

Bacteria

How did scientists create bacteria which were resistant to the antibiotic kanamycin?

They inserted a kanamycin resistance gene into a bacterial cell

What is the first stage in producing genetically modified bacteria?

A useful gene (gene of interest) is cut from the DNA of one organism using an enzyme called a restriction enzyme

How does the restriction enzyme cut DNA?

By breaking bonds between nucleotides

What happens as a result of the restriction enzyme cutting the DNA in a staggered way?

It leaves short sections of single-stranded DNA at each end of the gene. These sections of single-stranded DNA are called sticky ends

What is the second stage in producing genetically modified bacteria, after the useful gene is cut from one organism?

The bacterial plasmid DNA is cut open using the same restriction enzyme. The cut ends of the plasmid also have sticky ends

What is the third stage in producing genetically modified bacteria, after the bacterial plasmid DNA has been cut open?

The useful gene and the plasmid DNA are mixed and the gene is inserted into the plasmid. Hydrogen bonds form between the complementary bases in the sticky ends of the plasmid and the useful gene

What is the fourth stage in producing genetically modified bacteria, after hydrogen bonds have formed between the sticky ends?

The enzyme DNA ligase is used to join the plasmid DNA and the useful gene together. The ligase joins the end nucleotides of the useful gene to the end nucleotides of the plasmid

Why is the plasmid formed in genetic modification known as recombinant?

The plasmid now has DNA from more than one source

What is the final stage in producing genetically modified bacteria, after the recombinant plasmid has been formed?

The recombinant plasmid is inserted into a bacterial cell

In genetic modification, what does the recombinant plasmid act as, and why?

It acts as a vector because it carries the gene into the bacterial cell

Give four examples of types of protein produced by genetically modified bacteria.

• Hormones

• Antibiotics

• Enzymes

• Blood clotting factors

Give an example of a hormone produced by genetically modified bacteria.

Insulin

Give an example of an antibiotic produced by genetically modified bacteria.

Penicillin

Give an example of an enzyme produced by genetically modified bacteria.

Rennin used in cheese production

Give an example of a blood clotting factor produced by genetically modified bacteria.

Factor VIII used to treat haemophilia

Why is the technique used to genetically modify plant cells different to that used to create GM bacteria?

Because plant cells do not have plasmids

Which bacteria are commonly used to create GM plants, and why?

Agrobacterium tumefaciens because they have a Ti plasmid