B6.2 Feeding the Human Race 2

Question 1

Genetic engineering

Answer 1

When scientists alter an organism’s genome to produce an organism with desired characteristics
- v. Accurate as single genes can be targeted, occurs in 1 generation

Question 2

How have scientists genetically engineered cotton?

Answer 2

Increase crop yield from same area of land

Question 3

How have scientists genetically engineered corn?

Answer 3

To produce toxins that kill insects, making plant resistant to pests so smaller amounts of pesticides needed

Question 4

How have scientists genetically engineered bacteria?

Answer 4

To produce medical drugs like insulin/drugs to treat diseases domesticated in animals

Question 5

Risks of genetic engineering

Answer 5

• eating genetically engineered organisms may lead to health problems (eg. new allergen)
• genetically engineered crops may cross pollinate with wild plants, introducing new gene to wild plants, disrupting balance of ecosystem
• unethical? Science interfering with nature
• new and no one is sure of long term effects

Question 6

Basic steps to genetic engineering

Answer 6

1. Identify genes coding for the desired characteristic
2. Remove gene from donor host
3. Insert gene into host organism (often bacterium)

Question 7

Restriction enzymes

Answer 7

They cut donor DNA at specific base sequences, either side of desired gene
Same restriction enzymes used to cut open bacterial plasmid

Question 8

Sticky ends

Answer 8

restriction enzymes make staggered cut, leaving a few exposed, unpaired bases on ends of DNA attached

Question 9

Ligase enzymes

Answer 9

Used to rejoin DNA at the sticky ends as both host + donor have the same sticky ends = new gene joined to plasmid DNA

Question 10

Differences between cloning and genetic engineering

Answer 10

Cloning - produces exact copier
Genetic engineering - produces a unique set of genes

Cloning- genes copied within the same species
Genetic engineering- genes transferred between species

Question 11

First steps to genetically engineering bacteria to produce insulin

Answer 11

• insulin gene is removed from human DNA. Gene is cut from rest of DNA by restriction enzymes
• loop of bacterial DNA called plasmid is removed from the bacterial cell

Question 12

Second steps to genetically engineering bacteria to produce insulin

Answer 12

-the loop of DNA is cut ope using the same restriction enzymes that were used to cut the insulin gene from the human DNA

Question 13

Third steps to genetically engineering bacteria to produce insulin

Answer 13

-human insulin gene and loop of DNA are mixed, the human gene becomes inserted between the cut ends of the loop of DNA. Cut surfaces are repaired using the enzyme DNA ligase

Question 14

Fourth steps to genetically engineering bacteria to produce insulin

Answer 14

Repaired loop of DNA now carrying the human gene is then inserted into a new bacterium. The plasmid is called a vector- it carried the human gene

Question 15

Fifth steps to genetically engineering bacteria to produce insulin

Answer 15

The bacteria are now called transgenic bacteria because they have DNA from another organism. They are grown in large numbers to produce the insulin for us

Question 16

How to check that the gene had successfully transferred into the host’s genome

Answer 16

• insert an antibiotic resistance gene into the plasmid at the same time as inserting the gene coding for the desired characteristic
• transfer bacteria to an agar plate containing the selected antibiotic. Incubate and allow time for bacteria to grow
• any bacterial colonies present will survive because they now contain the antibiotic resistance marker gene as well as the desired gene

Question 17

What happens to transgenic bacteria?

Answer 17

They are then placed into fermenter units which provide optimum conditions for bacterial growth. Bacteria replicate and are killed by the heat, leaving behind insulin

Question 18

Biotechnology

Answer 18

The use of biological processes or living organisms to manufacture products
(Eg. Genetically modified organisms)

Question 19

Genetically modified

Answer 19

(gam) = genetically engineered but in reference to plants c animals

Question 20

Golden rice

Answer 20

(GM) created when a gene is taken from a daffodil and placed into rice —> rice produced beta-carotene which body uses to make vitamin A

Question 21

Bt corn

Answer 21

(g
GM) produced by inserting a gene into maize from the bacterium ‘Bacillus thuringiensis’ —> gene codes for a protein that is poisonous to insect pests, corn produces poison, kills pets trying to eat it

Question 22

Extra step in genetically modifying plants/animals

Answer 22

INSERTION = Useful gene is spliced into carrier DNA, combined DNA is placed in a virus, virus injected into plant cell
(Plasmids, bacteria and viruses can all be used as vectors to transfer foreign DNA into an organism)