Stem Cells

Stem Cells

What Are Stem Cells?

Stem cells are undifferentiated cells – they haven’t specialised yet.


They can divide to make more stem cells or differentiate into many different types of specialised cell.

 

💡 Key concept: Stem cells are the body’s raw materials – they can become any type of cell (in early development) or a limited range (in adults).

Types of Stem Cells

Type

Where Found

What They Can Become

Embryonic stem cells

In early embryos

Any type of cell in the body (pluripotent)

Adult stem cells

In bone marrow, etc.

Limited cell types (e.g. blood, bone, immune cells)

Plant stem cells

In meristems

Any type of plant cell, even throughout life

Uses of Stem Cells

In Medicine:

✔ Treat diseases like diabetes, paralysis, and leukaemia
✔ Replace damaged cells (e.g. new nerve or blood cells)
✔ Used in bone marrow transplants
✔ Future potential in growing organs for transplant

In Plants:

✔ Used to clone plants quickly and cheaply
✔ Protect rare species
✔ Produce plants with desirable traits (e.g. disease resistance)

Ethical Issues

Some people are concerned about using embryonic stem cells, because:

❌ The embryo is destroyed in the process
❌ Some believe it is morally wrong to use potential life
✔ Others argue it helps save actual lives

 

🔄 Adult stem cells are less controversial, but less versatile

Key Terms

  • Differentiation – when a stem cell becomes specialised
  • Pluripotent – can become most types of cells (like embryonic stem cells)
  • Therapeutic cloning – making an embryo with the same DNA as a patient
GCSE Biology diagram: a central stem cell with six specialised cells around it—muscle, sperm, root hair, red blood cell, palisade cell and nerve—illustrating differentiation
Stem cell surrounded by six specialised cells—muscle, sperm, root hair, red blood cell, palisade cell and nerve

Questions 

  1. What is a stem cell?
  2. Where are adult stem cells found?
  3. What can embryonic stem cells become?
  4. What is therapeutic cloning?
  5. Why are plant stem cells useful in farming?

Summary 

  • Stem cells can develop into many types of specialised cell.
  • Embryonic stem cells are more versatile than adult stem cells.
  • Therapeutic cloning is a potential medical breakthrough.
  • Plant stem cells help with cloning, conservation, and agriculture.
  • There are ethical concerns around embryonic stem cell use.