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Stem cells

Cell biology · Cell division · note 3 of 3

Stem cellsSpec 4.1.2.3

In short

A stem cell is an undifferentiated cell that can give rise to many more cells of the same type, and from which certain other cells can arise by differentiation. Stem cells are found in human embryos, adult bone marrow and plant meristems. They may help treat conditions such as diabetes and paralysis, but there are risks, such as transfer of viral infection.

Stem cell
An undifferentiated cell of an organism which is capable of giving rise to many more cells of the same type, and from which certain other cells can arise from differentiation.

You should be able to describe the function of stem cells in embryos, in adult animals and in the meristems in plants.

WhereWhat the stem cells can do
Human embryosCan be cloned and made to differentiate into most different types of human cell
Adult bone marrowCan form many types of cell, including blood cells
Plant meristemsMeristem tissue can differentiate into any type of plant cell, throughout the life of the plant

Knowledge and understanding of stem cell techniques are not required.

Medical uses

Treatment with stem cells may be able to help conditions such as diabetes and paralysis.

In therapeutic cloning an embryo is produced with the same genes as the patient. Stem cells from the embryo are not rejected by the patient's body, so they may be used for medical treatment.

Risks and objections

  • There are potential risks, such as transfer of viral infection.
  • Some people have ethical or religious objections to the use of stem cells from embryos.
Exam tip:

In evaluation questions, give at least one benefit and one risk or objection, then reach a conclusion. Compare the medical benefit to patients with the ethical concerns of others.

Plant stem cells

Stem cells from meristems in plants can be used to produce clones of plants quickly and economically.

  • Rare species can be cloned to protect them from extinction.
  • Crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers.

Quick check

  1. What are chromosomes made of, and where are they found?

    Show answer

    DNA molecules, in the nucleus.

  2. Name the three overall stages of the cell cycle.

    Show answer

    Growth and DNA replication; mitosis; division of the cytoplasm and cell membranes.

  3. What does mitosis produce?

    Show answer

    Two genetically identical cells.

  4. Why are stem cells from therapeutic cloning not rejected?

    Show answer

    The embryo has the same genes as the patient.

  5. Where are stem cells found in plants?

    Show answer

    In meristems, throughout the life of the plant.

Written and checked against the AQA GCSE Combined Science (8464) specification · Updated October 2026

Frequently asked questions

What are the stages of mitosis?

For AQA GCSE you need the three overall stages of the cell cycle, not the separate phases of mitosis. First the cell grows, makes more sub-cellular structures and replicates its DNA. Then, in mitosis, one set of chromosomes is pulled to each end of the cell and the nucleus divides. Finally the cytoplasm and cell membranes divide.

Why is mitosis important?

Mitosis is important for the growth and development of multicellular organisms, because it produces new cells that are genetically identical to the parent cell. In mature animals, cell division is mainly restricted to repair and replacement, for example when new skin cells heal a cut. It also happens as root and shoot tips lengthen.

Why are stem cells useful in medicine?

Stem cells are useful because they are undifferentiated and can differentiate into other types of cell. Treatment with stem cells may be able to help conditions such as diabetes and paralysis. In therapeutic cloning, an embryo with the same genes as the patient is produced, so its stem cells are not rejected by the patient's body.

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