Stem Cells

Human Stem Cells

• Stem cells are UNDIFFERENTIATED cells capable of becoming other types of cells, undergoing a process known as DIFFERENTIATION.
• A stem cell can also divide to make many more cells of the SAME TYPE as itself.

HUMANS have TWO types of stem cells:

1. Stem cells found in early HUMAN EMBRYOS, which can be cloned and made to differentiate into MOST types of human cell.

2. ADULT STEM CELLS exist too but are more limited in the types of cells they can turn into. They are commonly found in BONE MARROW and can form MANY types of cell, INCLUDING BLOOD CELLS (e.g. RED blood cells and WHITE blood cells).

Healing with Stem Cells

STEM CELLS can be grown in labs and differentiated into specialised cells for MEDICINE or RESEARCH.

Examples include:

• ADULT STEM CELLS can be used to treat diseases by replacing faulty BLOOD CELLS in patients.
• EMBRYONIC STEM CELLS have potential in treating a variety of conditions, including DIABETES and PARALYSIS caused by spinal injuries.
• THERAPEUTIC CLONING involves creating an embryo with the same GENES as the patient. Stem cells taken from that embryo carry the same genetic information as the patient, so they are not REJECTED by the patient's body.

Risks and Ethical Considerations

• Stem cells are grown outside the body before being given to a patient, so there is a risk of transferring a VIRAL INFECTION.
• Debate surrounds stem cell research, particularly concerning the use of human embryos.
• People AGAINST stem cell research have ETHICAL or RELIGIOUS objections to using POTENTIAL HUMAN LIVES for experiments.
• People FOR stem cell research argue that benefits for SUFFERING PATIENTS are more important than the rights of an embryo.
• Stem cell research is regulated, with some countries having bans and others allowing it under strict conditions.

Plant Stem Cells

• In plants, stem cells are found in MERISTEM TISSUE, which is on the TIPS of plant shoots and roots where growth occurs.

• Unlike adult human stem cells, meristem tissue can differentiate into ANY type of plant cell, and it keeps this ability THROUGHOUT THE LIFE of the plant.
• These stem cells can be used to produce identical CLONES of plants QUICKLY and ECONOMICALLY.
• This technique is useful for preserving RARE SPECIES of plants from EXTINCTION, and for producing large numbers of identical CROPS for farmers with desirable traits like DISEASE and INSECTICIDE RESISTANCE.