B6.2.5

Question 1

How are organisms genetically engineered

Answer 1

1. Identify gene that codes for the desired characteristic
2. Remove gene from donor organism
3. Insert the gene into a host organism, often bacterium

Question 2

Why do scientists genetically engineer bacteria

Answer 2

To produce useful substances including hormones, vaccines and antibodies.

Question 3

What are used to move genes between organisms

Answer 3

Enzymes

Question 4

What do restriction enzymes do

Answer 4

Restriction enzymes cut the donor DNA at specific base sequences. They make a staggered cut, leaving few exposed unpaired bases on the ends of the DNA strands. These are called “sticky ends”. The same restriction enzymes are used to cut open the bacterial plasmid.

Question 5

What are ligase enzymes used for

Answer 5

They region the DNA strands at the sticky ends. As both host and donor DNA have the same sticky ends, the new gene is joined into the plasmid DNA.

Question 6

What is the plasmid called

Answer 6

They are called vectors.

Question 7

Because genetic engineering was not always successful what do scientists do

Answer 7

Need to check that the gene has been successfully transferred into the hosts’s genome

Question 8

What is a method to check that the gene has been transferred

Answer 8

To add a gene for antibiotic resistance into the plasmid at the same time as inserting the gene coding for the desired characteristic.
Transfer the bacteria to an agar late containing the selected antibiotic. Incubate and allow time for the bacteria to grow.
Any bacterial colonies present will survive because they now contain the antibiotic resistance marker gear. These bacteria will also contain the desired gene.