22: Genetic Modification

Question 1

What is Recombinant DNA

Answer 1

Recombinant DNA is DNA made from genetic engineering, by combining DNA of two different species of organisms.

Question 2

What is Transgenic?

Answer 2

Transgenic are Organisms that have been engineered with a gene from another species.

Question 3

What are Plasmids?

Answer 3

Plasmids are Small circular pieces of DNA found in bacteria which is used in genetic engineering.

Question 4

What are Restriction endonucleases (enzyme)?

Answer 4

It is an enzyme used in genetic engineering to cut out a section from a molecule of DNA. These enzymes cut DNA at specific nucleotide sequences, resulting in fragments with sticky ends.

Question 5

What are Ligases?

Answer 5

Ligases are Enzymes that digest lipids.

Question 6

What is Vector (in biology)?

Answer 6

Vector is a structure which can be used to transfer genes in genetic engineering, e.g. a plasmid.

Question 7

What is Bacteriophage?

Answer 7

Bacteriophage is a virus that infects bacteria. Used as a vector in genetic engineering.

Question 8

The protein that is produced by the genes in a DNA could be:

Answer 8

-an enzyme that controls a particular reaction inside a cell or in the digestive system
-a structural protein like keratin in hair, collagen in skin, myosin in muscles or one of many proteins found in the membranes of cells
-a protein hormone such as insulin
-a protein with a specific function such as haemoglobin or an antibody

Question 9

An example of a transgenic organism

Answer 9

An example of a transgenic organism is a sheep that secretes alpha-1-antitrypsin in its milk because it has been genetically engineered by a human gene that makes this substance.

Question 10

What is alpha-1-antitrypsin?

Answer 10

AAT is a protein made in a human liver to help protect the lungs.

Question 11

Steps to genetically modify a bacteria (4)

Answer 11

1. plasmids are isolated from bacteria and opened up using a restriction enzyme.
2. The gene to be transfered is cut from the donor DNA using a restriction enzyme.
3. The opened-up plasmids and the isolated gene are mixed with a DNA ligase enzyme to create recombinant plasmids.
4. Bacteria are incubated with the recombinant plasmids. And some will take up the plasmids.

Question 12

How bacteriophage are used to genetically modify bacteria (3)

Answer 12

1. Bacteriophage attaches itself to the cell wall of the bacterium.
2. It injects its DNA into the bacterium.
3. The foreign gene is taken up by the bacterial DNA.

Question 13

Some examples of enzymes and what they digest (4)

Answer 13

-Amylase digest starch
-Proteases digest proteins like blood stains
-Lipases digest lipids like grease marks
-glucose isomerase catalyses a reaction which converts glucose into fructose.

Question 14

Six examples of products manufactured by genetically modified bacteria

Answer 14

1. Human insulin
2. Human vaccines
3. Human growth hormone
4. Enzymes for washing powders
5. Enzymes in the food industry
6. Bovine somatotrophin

Question 15

What is bovine somatotrophin

Answer 15

BST is a growth hormone in cattle which increases milk yield in cows and muscle production in bulls.

Question 16

Any procedure for genetically modifying plants has two main stages:

Answer 16

1. Introducing the new genes into plant cells.
2. Producing whole plants from just a few cells.

Question 17

What is Agrobacterium tumefaciens?

Answer 17

Agrobacterium tumefaciens is a soil bacterium which regularly inserts plasmids into plant cells. It is used as a vector in genetically modifying plants.

Question 18

How plants are genetically modified using agrobacterium:

Answer 18

1. First steps are similar to how bacteria are genetically modified.
2. Except the leaf discs float on liquid that contains these recombinant plasmids.
3. When some take up the plasmids they are cultivated on a nutrient medium, which then are grown into whole plants.

Question 19

How are cereal plants genetically modified?

Answer 19

Tiny golden pellets coated with DNA that contains the desired genes are fired inside the plant tissue using a gene gun, as agrobacterium cannot infect them. They are then micropropagated like agrobacterium infected plant cells.

Question 20

Examples of genetically modified plants (4)

Answer 20

-Fruits and vegetables engineered to have extended shelf lives.
-Some crop plants engineered to be resistant to herbicides, allowing farmers to spray weedkillers without affecting the crops.
-Some plants engineered to be frost resistant by genes from arctic fish that code for an ‘anti-freeze’ in their blood.
-‘golden rice’ which is a GM rice which has 3 foreign genes in its DNA (2 from daffodils and 1 from a bacterium) that allow the rice to make beta-carotene which is converted into vitamin A when eaten.

Question 21

Examples of GM plants used to help humans resist infection

Answer 21

-GM tobacco plants and soybeans produce antibodies against a range of infectious diseases.
-Some GM tobacco plants produce the hepatitis B antigens that could be used as a basis for a vaccine.

Question 22

Benefits that genetic modification could provide to plants

Answer 22

-increased resistance to a range of pests and pathogens
-Increased tolerance to salt, heat and drought
-A better balance of proteins, carbohydrates, lipids, vitamins and minerals.

Question 23

How are animals genetically modified?

Answer 23

1. The required gene is cut out from a DNA using a restriction enzyme.
2. The DNA is injected into a fertilised egg from a donor animal.
3. The eggs are then put into a surrogate mother.

Question 24

Benefits achieved by GM animals: (4)

Answer 24

-Manufacture of human proteins, e.g. antibodies, blood clotting factors or alpha-1-antitrypsin.
-Increased production of a particular product, e.g. higher milk yield in cows, greater muscle mass in animals used for meat.
-increased resistance to disease.
-Production of organs for transplantation.

Question 25

What is Xenotransplantation?

Answer 25

Xenotransplantation is transplanting organs from other animals into humans.

Question 26

What is polymerase chain reaction?

Answer 26

PCR is a laboratory process that rapidly produces a large number of copies of a piece of DNA, starting from as little as one molecule.