Cell Differentiation and Stem Cells

Cell differentiation is the process by which a cell changes from one type to another, usually becoming more specialised.
During this process, different genes within the cell’s DNA are expressed or switched off, allowing the cell to perform different roles.
Specialisation allows cells to perform functions more effectively, as they develop structures suited to their purpose.
All cells in an organism originally come from a single fertilised egg (zygote).
Differentiation mostly takes place during the development of an organism.
However, there are also adult stem cells in certain tissues which can differentiate throughout an organism’s life.

There are many types of differentiated cells, including neurons, muscle cells, and blood cells.
Muscle cells, for example, become specialised for contraction, developing many mitochondria for energy and proteins that allow them to contract.
Red blood cells become specialised for transporting oxygen, losing their nucleus and other organelles to make room for haemoglobin.
Neurons become specialised for transmitting signals, developing long extensions and branching connections to other neurons.

Stem cells are undifferentiated cells that have the potential to become any type of cell in the body.
They are unique because they have the ability to self-renew and differentiate into specialized cell types.
Stem cells can be found in different parts of the body, including the bone marrow, umbilical cord blood, and embryos.
Embryonic stem cells are pluripotent, meaning they can differentiate into almost any cell type, whilst adult stem cells are generally more limited in their differentiation potential.

Stem cells have the potential for Regenerative medicine, where damaged or lost tissues could be replaced. This can potentially treat conditions like spinal cord injuries or degenerative diseases like Parkinson’s.
However, there are ethical issues linked to the use of stem cells, particularly embryonic stem cells, as the process of collection can destroy the embryo.
Using adult stem cells avoids these ethical issues, but they are less versatile and harder to collect.
Therapeutic cloning could potentially be a way to produce stem cells which are genetically identical to the patient, avoiding issues with immune rejection. However, this also raises considerable ethical controversy.