IB MYP 4-5 Biology-Cloning- Study Notes - New Syllabus
IB MYP 4-5 Biology-Cloning- Study Notes – New syllabus
IB MYP 4-5 Biology-Cloning- Study Notes – IB MYP 4-5 Biology – per latest IB MYP Biology Syllabus.
Key Concepts:
- Therapeutic vs reproductive cloning
- Somatic cell nuclear transfer (Dolly the sheep)
- Plant tissue culture
- Applications in conservation
Cloning
What Is Cloning?
Cloning is the process of creating an exact genetic copy of a gene, cell, or entire organism. A clone has the same DNA as the original – like a biological photocopy.
Types of Cloning
There are two main types of cloning used in biotechnology and medicine:
1. Reproductive Cloning
What It Is: Used to create a whole new organism that is genetically identical to the original.
How It Works:
- A body cell (e.g., skin cell) is taken from the donor organism
- The nucleus (DNA) is extracted and inserted into an empty egg cell
- The egg is stimulated to divide and form an embryo
- The embryo is implanted into a surrogate mother
Example: Dolly the sheep – first cloned mammal (1996)
Uses:
- Reproduce animals with desirable traits
- Preserve endangered species
- Study genetics and hereditary diseases
Concerns:
- Low success rate, high cost
- Ethical issues, especially with human cloning
- Health problems and shortened lifespan in clones
2. Therapeutic Cloning
What It Is: Creates embryonic stem cells for medical treatment, not for developing a full organism.
How It Works:
- Similar to reproductive cloning – but the embryo is not implanted
- Stem cells are extracted from the embryo
- These cells can develop into different types of tissues or organs
Uses:
- Regenerate organs like heart, liver, pancreas
- Treat diseases such as Parkinson’s, spinal injuries, and diabetes
- Research into early development and genetic disorders
Concerns:
- Ethical debates over embryo use
- Still under development – not widely available
- Risk of misuse without proper regulation
Reproductive vs Therapeutic Cloning
| Feature | Reproductive Cloning | Therapeutic Cloning |
|---|---|---|
| Purpose | Create a whole organism | Produce stem cells for treatment |
| Involves embryo? | Yes, implanted | Yes, but not implanted |
| End result | A cloned individual | Stem cells or tissues |
| Real-world use | Animal reproduction | Regenerative medicine |
| Ethical issues | High | Medium to High |
Cloning means copying life at the genetic level.
Reproductive cloning creates new organisms, while therapeutic cloning creates healing cells.
Both offer great potential – and raise important ethical questions.
Somatic Cell Nuclear Transfer (SCNT)
What Is SCNT?
Somatic Cell Nuclear Transfer (SCNT) is a cloning technique where the nucleus of a body (somatic) cell is transferred into an empty egg cell. It was the method used to create Dolly the Sheep the world’s first cloned mammal from an adult cell, in 1996.
Breaking Down the Name
| Term | Meaning |
|---|---|
| Somatic cell | Anybody cell (not sperm or egg), like skin or muscle |
| Nuclear | Refers to the nucleus, which contains DNA |
| Transfer | Moving the nucleus from one cell to another |
SCNT – Step-by-Step Process
- Take a somatic cell (e.g., a skin cell) from the animal to be cloned
- Remove its nucleus, which contains the DNA
- Take a healthy egg cell from a donor animal
- Remove the egg’s nucleus (make it empty)
- Insert the somatic nucleus into the empty egg
- Use an electric shock or chemical to activate the egg
- The egg begins to divide like a normal embryo
- Transfer the embryo into a surrogate mother
- A clone is born, genetically identical to the somatic cell donor
Example: Dolly the Sheep
- Born in 1996 in Scotland
- Cloned from an adult mammary gland (udder) cell
- Proved adult cells can be reprogrammed into new organisms
- Lived for 6.5 years and died of lung disease
Opened doors to modern cloning and stem cell research
Why SCNT Matters
| Benefit | Why It’s Important |
|---|---|
| Advances cloning research | Showed that full cloning from adult cells is possible |
| Aids therapeutic cloning | Can create embryos for stem cell studies |
| Helps preserve rare species | Enables cloning of endangered animals |
| Improves understanding of cells | Helps scientists study development and differentiation |
Concerns and Risks
- Low success rate: Many embryos fail to survive or develop properly
- Health problems in clones: Premature aging and defects are common
- Ethical questions: Debates around cloning of animals or humans
- Genetic sameness: Reduces diversity in populations
It allows scientists to copy organisms using body cells, but also brings ethical, scientific, and biological challenges.
Plant Tissue Culture
What Is Plant Tissue Culture?
Plant tissue culture is a method where small parts of a plant (like cells, tissues, or organs) are grown in sterile lab conditions on a special nutrient medium. It allows scientists to produce many identical plants – quickly and without using seeds.
Key Concept: Totipotency
Totipotency means that every plant cell has the potential to grow into a complete plant, given the right conditions. This is the scientific basis of tissue culture one small part can grow into the whole.
Basic Steps in Plant Tissue Culture
- Select a plant part (explant) like a leaf, stem, root tip, or meristem
- Sterilize the explant to kill bacteria and fungi
- Place it on a nutrient-rich agar medium with sugars, minerals, and hormones
- Maintain in controlled conditions (light, temperature, humidity)
- Cells divide and form a callus (mass of cells)
- Callus develops shoots and roots with the right hormones
- Transfer the plantlets to soil for normal growth
Uses of Plant Tissue Culture
| Field | Application |
|---|---|
| Agriculture | Mass-produce disease-free and high-yield crops |
| Research | Study plant growth and genetics |
| Conservation | Save rare or endangered plant species |
| Horticulture | Grow ornamental plants like orchids and roses |
| Environment | Reforestation with selected tree species |
Advantages of Plant Tissue Culture
| Benefit | Why It Matters |
|---|---|
| Rapid multiplication | Produces thousands of plants quickly |
| Genetically identical plants | Useful for preserving desired traits |
| Disease-free plants | Sterile technique prevents infections |
| Year-round production | Independent of seasonal limitations |
| No seeds required | Uses small plant parts instead |
Limitations of Tissue Culture
- Expensive setup: Requires advanced equipment and skilled technicians
- Contamination risk: Infections can destroy entire cultures
- Lack of variation: All clones have the same genetic makeup
- Ethical concerns (with GM): Raised when genetic modification is used
Real-Life Examples
Banana and sugarcane industries in India use tissue culture for uniform, disease-free plants
Orchid farming uses this method to grow large numbers of decorative plants for commercial sale
Summary:
Plant tissue culture allows us to grow many healthy, identical plants from just one tiny part. It’s fast, clean, and efficient and is a vital tool in agriculture, plant research, and biodiversity conservation.
Applications in Conservation
What Is Conservation?
Conservation means protecting natural species, genetic diversity, and ecosystems for future generations. It includes preventing extinction, restoring populations, and safeguarding habitats.
Role of Tissue Culture in Conservation
Plant tissue culture helps in conservation by cloning rare, endangered, or valuable plant species. It allows scientists to regrow plants from very small samples, even if the plant is nearly extinct in the wild.
It is a key method in ex situ conservation – protecting species outside their natural habitat.
Key Conservation Applications
1. Rescuing Endangered Plants
Some plants are close to extinction due to deforestation, climate change, or over-harvesting. Tissue culture helps produce many healthy plants from a few remaining cells. These can be reintroduced into the wild or preserved in botanical gardens.
Example: Rauvolfia serpentina (medicinal) and Nepenthes (pitcher plants).
2. Preserving Rare Genes (Gene Banks)
Living plant cells are stored in labs under low-temperature or slow-growth conditions. These serve as genetic backups and can be used to restart plant populations if wild types are lost.
3. Propagation of Medicinal & Wild Plants
Medicinal plants are often overharvested. Tissue culture allows for sustainable lab-based growth, protecting wild stocks and preventing illegal trade.
Example: Aloe vera, Bacopa monnieri, Withania somnifera (Ashwagandha)
4. Supporting Reforestation
Trees like teak and sandalwood, which have poor seed germination, can be mass-grown using tissue culture. This supports eco-restoration of degraded forests.
Benefits for Conservation
| Benefit | Explanation |
|---|---|
| Mass production | Thousands of plants from a small sample |
| Gene preservation | Rare traits stored safely in labs |
| Disease-free planting stock | Clean and healthy plants ready for reintroduction |
| Habitat restoration | Rebuilds forests and grasslands |
| Space-saving storage | Cultures need less space than full-grown plants |
Challenges and Ethical Issues
- Costly setup: Requires sterile lab conditions and trained personnel
- Limited to plants: Cannot be used directly for animal conservation
- Genetic uniformity: Risk of reduced diversity in cloned populations
- Ownership concerns: Legal and ethical debates about rights over native or traditional plant varieties
Plant tissue culture is more than a lab tool – it’s a lifeline for many rare, medicinal, and endangered species. By cloning plants, storing their cells, and supporting reforestation, it plays a crucial role in building a greener, more biodiverse future.