Selective Breeding, Cloning And Genetic Engineering

Question 1

What is selective breeding

Answer 1

The process in which humans breed plants and animals for particular genetic characteristics

Question 2

By breeding a member of a species with a desired trait..

Answer 2

that traits frequency becomes more common in the next generations

Question 3

How can you end up with all offspring showing a desired characteristics

Answer 3

Keep breeding the offspring with the desired characteristics over many generations until all the offspring show the desired characteristic

Question 4

The desired characteristic can be used for what

Answer 4

Appearance and usefulness such as:
- disease resistant crops
- animals that produce more meat/milk
- larger more unusual flowers
- more gentle temperament dogs

Question 5

Problems with selective breeding - new disease and reduction in the gene pool

Answer 5

• More chance of the population the be wiped out completely by disease: Reduction in the gene pool - the number of different alleles in the population which means the members of a species are closer together, meaning that possibly none of the species will have a resistant gene to a disease and can all be fully wiped out

Question 6

3 disadvantages of selective breeding

Answer 6

1. Can lead to a reduction in the gene pool
2. Higher chance in an allele of a harmful genetic disease or defect is passed on
3. New diseases and defects can occur due to the reduced gene pool

Question 7

What is genetic engineering

Answer 7

The process of modifying the geonome of an organism by transferring genes to achieve desired characteristics

Question 8

2 uses of genetic engineering

Answer 8

1. Plant crops to be resistant to diseases and produce bigger and better fruits
2. Bacteria cells have been genetically engineered to produce useful substances like human insulin to treat diabetes

Question 9

Organisms that have been genetically engineered and given genes from other organisms are known as

Answer 9

Transgenic

Question 10

Crops that have been genetically engineered and have had their genes modified are know as what

Answer 10

Genetically modified

Question 11

What is the process of genetic engineering (1-6)

Answer 11

1. Scientist use restriction enzymes to cut a segment of DNA that contains the gene with the desired characteristic. This leaves sticky ends to the gene
2. A plasmid is extracted from a bacterium
3. The plasmid is cut with the same restriction enzyme
4. The plasmid and gene are joined together using the enzyme ligase, forming a hybrid/ recombinant plasmid
5. The recombinant plasmid is put back into the bacteria cell, acting as a vector as it transfers the gene from one organism to the target (TRANSGENIC) organism
6. The vector cell (bacteria cell) is then inserted into the required cells

Question 12

Benefits of genetically modified organisms

Answer 12

Nutritional value improved
Can grow easier - higher yield
Ability to be pest resistant
Longer shelf shelves
Reduces economic cost and carbon footprint - less land needed

Question 13

Examples of genetic engineering

Answer 13

Sheep to produce specific substances in their milk
Genetically modified crops to increase size
Treating diabetes with the insulin produced

Question 14

Risks of genetically modified organisms

Answer 14

New traits can cause new health problems
Unknown effects of removing traits
Some governments disagree with it

Question 15

What is cloning

Answer 15

Genetically identical clones of an organism - asexual reproduction

Question 16

What are the 2 types of cloning in plants

Answer 16

Cuttings
Tissue culturing

Question 17

What are the 2 types of cloning in animals

Answer 17

Adult cell cloning
Embryo transplants

Question 18

Describe the process of tissue culturing and its benefits

Answer 18

• A few plant cells are put in a growth medium with hormones and they then grow into clones of the parent plant.
  -Advantages - Can be made very quickly, in very little space and grown all year round, can also be used to preserve rare plants by making lots of them

Question 19

Describe the process of cloning by
cuttings

3 steps

Answer 19

1. A shoot cutting is taken from the plant with the desired characteristics
2. Place this cut end it rooting powder and in moist compost to prevent wilting
3. Plant produced is genetically identical to original plant

Question 20

Describe the process of cloning by embryo transplant

3 steps

Answer 20

1. Sperm taken from the prize male animal and female is inseminated with the sperm.
2. Zygotes develop into embryos in female and then are removed from the uterus, the embryos are then split into several smaller embryos which each grow into a new calf
3. These embryos are then placed into the uterus of the foster mother
   - The new embryos will be genetically identical to each other but will not share genetic material
   Host mother known as surrogate

Question 21

Describe the process of cloning by adult cell culturing

4 steps

Answer 21

1. Nucleus is removed from an unfertilised egg (ovum), which is now enucleated
2. The nucleus from an adult body cell, such as a skin cell, is inserted into the egg cell, the nucleus contains genetic information
3. An electric shock stimulates the egg cell to divide by mitosis to form an embryo, which contain the same genetic information as the adult skin cell
4. When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female (surrogate) and continues ti develop

Question 22

Positives of cloning

5

Answer 22

Rare plants can be saved
Process is simple and quick
Allows mass production in short amount of time
Leads to better embryo understanding

Question 23

Negatives of cloning

4

Answer 23

Ethical issues - morally wrong to manipulate cells without consent
Mass production leads to reduced gene pool
Worries of cloning of people