Country: United States
Date: Summer 2010
If all cells in the human body contain the same strand of
DNA, how does cells in different parts of the body know to function
correctly? (i.e. how does a cell know that it is an eye cell and not
a heart cell?)
Cells use a complicated set of signaling molecules that govern which
proteins they express, and therefore which form and function they
take. Cells can respond to a whole variety of compounds in minute,
minute quantities, such as salts, proteins, hormones, and many more.
Scientists are just scratching the surface on all the components that
play a role, and how they all work together. Many scientists are
working on figuring out the exact environment and recipe required to
coax a cell to differentiate (turn into a different type of cell) into
a desired form.
There is current research showing that
undifferentiated stem cells can be stimulated with various substances
to specialize into specific types of cells. However, once a cell
differentiates, it may or may not be able to convert to a different
kind of cell (usually it cannot). This is why stem cells are so
interesting to scientists, because they can still differentiate into
many other kinds of cells.
Hope this helps,
Different genes are expressed (turned on) in diferent cells.
Ron Baker, Ph.D.
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Update: June 2012