genetic engineering.

Question 1

what is genetic engineering?

Answer 1

changing the genome of an organism, often by introducing genes from another to create genetically modified organisms (GMOs)

Question 2

how does genetic engineering work?

Answer 2

1. the gene for a characteristic is ‘cut out’ of a chromosome using enzymes
2. the gene is inserted into a chromosome inside the nucleus of a cell in a different organism
3. the cell of this organism now produces the characteristic from the gene

Question 3

why are some crops genetically modified?

Answer 3

gives them new characteristics such as resistance to attack by insects, resistance to herbicides so that field can be sprayed to kill weeds but not the crops

these characteristics can help the crop grow better and produce more food (an increased yield)

Question 4

what do enzymes do in the formation of genetically modified bacteria?

Answer 4

they cut the required gene out of the human DNA, leaving ‘sticky ends’ on the gene
the same restriction enzymes cut open the plasmid, creating matching sticky ends
the DNA ligase enzyme joins the matching sticky ends of the human gene and the plasmid to make on complete modified plasmid

Question 5

what do restriction enzymes do?

Answer 5

these make staggered cuts across double stranded DNA, leaving a few unpaired bases at each end, called ‘sticky ends’

Question 6

how can human insulin be made?

Answer 6

it can be made in large quantities from bacteria that have been genetically modified to contain the gene for human insulin

Question 7

steps for making human insulin:

Answer 7

1. DNA from a human cell is cut into pieces using restriction enzymes
2. Bacteria cells contain small circles of DNA called plasmids. The same restriction enzymes are used to cut plasmids open, leaving sticky ends with matching sets of unpaired bases
3. the pieces of DNA containing the insulin gene are mixed up with the plasmids, the bases in the stick ends pair up. an enzyme called DNA ligase is added, linking the DNA back into a continuous circle
4. the plasmids are inserted into bacteria, which can be grown in huge fermenters where they make human insulin

Question 8

what is a vector?

Answer 8

a vector is the name for anything that carries the new gene into a cell