Cells and Control: Stem Cells

Stem cells are unspecialised cells that have the ability to divide many times, potentially on an indefinite basis.
When stem cells divide, they form new cells that can either remain as stem cells or differentiate into specialised cells, such as muscle or nerve cells.
Stem cells are found in both human embryos and adult human tissues. Embryonic stem cells have the potential to turn into any type of cell in the body.
Because of their ability to transform into any type of cell, stem cells have significant potential in medical treatment. They could be used to replace diseased or damaged cells in various conditions, such as Parkinson’s disease, spinal cord injury, or heart disease.
In plants, stem cells are found in meristems - regions of active cell division. They can differentiate into any type of plant cell and allow the plant to grow continuously.
Therapeutic cloning involves producing an embryo with the same genes as the patient, so the stem cells it produces will not be rejected by the patient’s immune system.
The use of stem cells in medicine holds a lot of promise, but it’s also controversial. These controversies focus on issues such as the ethics of using embryonic stem cells, which involves the destruction of embryos.
The extraction of stem cells from adults is less contentious, as it doesn’t involve embryos. However, these cells are not as flexible as embryonic stem cells – they can only develop into a limited range of cell types.
Cell differentiation is tightly controlled in the body through a variety of mechanisms, including the turning on/off of genes and the actions of specific proteins. Uncontrolled cell division can lead to cancer.
Controlling the differentiation of stem cells in the lab is a key challenge in stem cell research. Scientists are learning more about the signals that trigger stem cell differentiation, with the aim of guiding their development into specific cell types.