Cloning

What is the definition of cloning?

Creating an individual genetically identical to another organism

What are the two types of cloning, and give a definition for each

Natural Cloning-Occurs without human intervention

Artificial Cloning-Requires human intervention

What are the natural cloning examples in plants

• Rhizomes-Horizontal underground stems

• Stolons/Runners-Horizontal overground stems

• Suckers-shoots that grow from the roots or the bulbs

• Tubers-underground storage organs with ‘eyes’

• Bulbs-underground storage organs without eyes

How do you take cuttings?

1. Use sharp scalpel to take 5-10cm cutting

2. Remove leaves,leaving one at the tip

3. Dip in rooting powder

4. Place in moist growth medium and bag

How do you tissue culture plants?

1. Cut plant material into small explants

2. Sterilise explant

3. Place in growth medium

4. Add auxins and cytokinins to form callus

5. Subdivide plantlets

6. Transfer to greenhouse

What is another name for tissue culturing plants?

Micro propagation

What are the advantages of plant cloning?

• Faster than sexual reproduction

• Sustainable use

• Control of desired characteristics

• Genetic consistency

What are the disadvantages of plant cloning?

• Expensive

• Vulnerable to disease

• No genetic variation

What are the two animal cloning techniques?

Artificial embryo twinning and Somatic Cell Nuclear Transfer (SCNT)

How does artificial embryo twinning work?

-Fertilise egg cells in a lab with desired sperm

-Split developing cells

-Insert into surrogates,forming genetically identical embryos

How does SCNT work?

1. Extract somatic cell nucleus from organism you desire to clone

2. Remove nucleus n from unfertilised egg

3. Insert somatic cell nucleus using electrical fusion

4. Implant in surrogate

Explain the differences between natural and artificial cloning in animals [5]

Natural:

-Occurs without human intervention [1]

-Examples:Identical twins [1] or Pathogenesis [1]

Artificial:

- Occurs with human intervention [1]

-Methods: Artificial Embryo Twinning [1] and SCNT [1]

-Example: Cloning of genetically modified animals or clones for stem cells [1]

Describe the steps of tissue culturing in plant propagation [6]

1. Prepare explants [1]

2. Sterilise Explant [1] e.g with bleach

3. Place explant on growth medium [1], maintaining aseptic conditions [1]

4. Add high levels of auxins and cytokinins [1]

5. This will form a callus [1]

6. Divide the callus into plantlets [1]

7. Repeat hormone treatment [1]

8. Move to greenhouse once shoots start to form [1]

What are the advantages and disadvantages of cloning? [6]

Advantages (1 mark for each, max 4 marks): Faster reproduction compared to sexual reproduction,allows for sustainable use of plants in medicine, control desired characteristics due to identical genetic makeup ups, potential for stem cell growth and tissue regeneration,can preserve endangered species

Disadvantages (1 mark for each, max 4):Expensive, Clones are all vulnerable to the same diseases, High failure rate of cloned embryos, Many cloned animals die early, a ethical concerns surrounding the process

Give a difference between artificial embryo twinning and somatic cell nuclear transfer [1]

[1] Artificial embryo twinning involves splitting an early embryo into separate cells that develop into clones, while somatic cell nuclear transfer (SCNT) involves replacing the nucleus of an egg cell with the nucleus of a somatic cell, allowing for the development of a clone.

[2] Artificial embryo twinning involves two parents,while SCNT only involves one organisms genetic makeup

How do environmental factors affect cloning?

Environmental factors such as temperature, light, and nutrient availability can significantly influence the success of cloning by affecting growth rates, development processes, and overall viability of cloned organisms.

What is vegetative propagation?

Natural cloning of plants