Video Transcript
What is the key difference between
embryonic and adult stem cells? (A) Large numbers of adult stem
cells can be easily grown in culture, but embryonic stem cells can only divide
inside the body of the embryo. (B) Embryonic stem cells can
differentiate to become any type of specialized cell, but adult stem cells can only
become certain types of cells. (C) Adult stem cells can
differentiate to become any type of specialized cell, but embryonic stem cells can
only become certain types of cells. (D) Adult stem cells can divide
rapidly to make new cells, but embryonic stem cells take a long time to divide and
generate new cells. (E) They do not differ in any of
their properties.
This question is asking us about
the difference between embryonic and adult stem cells. Let’s remove these answer choices
so we have more room to work with.
A stem cell is an unspecialized
cell that can differentiate or change into a more specialized cell. For example, a blood stem cell can
differentiate into multiple cell types, like red blood cells, mast cells,
macrophages, and many others. These are more specialized cells
that are derived from the unspecialized blood stem cell. This blood stem cell also has the
ability for self-renewal, where it can divide to make new copies of itself to
replace the stem cells that have differentiated.
The ability to differentiate into
more specialized cells and to self-renew is a feature of all stem cells. So what’s the difference between an
embryonic and an adult stem cell?
Embryonic stem cells, as the name
suggests, are stem cells that come from embryos. These cells can give rise to any
kind of cell in the body, like neurons in the brain, epithelial cells in our skin,
or blood cells as we’ve already talked about.
To do this, embryonic stem cells
can differentiate into a different kind of stem cell called an adult stem cell. These adult stem cells are more
restricted in what they can differentiate into. And they are the ones that can
differentiate into specific cell types. So there are neural stem cells,
which are adult stem cells that give rise to many types of neurons. And there are blood stem cells that
give rise to the different types of blood cells as we can see here. A neural stem cell will only
differentiate into certain cell types that relate to the neural lineage and will not
be able to differentiate into blood cells. Specialized blood cells need to
differentiate from a blood stem cell. So embryonic stem cells can become
any cell type, while adult stem cells can only become certain cell types.
If we bring back the answer
choices, we can see that the key difference between embryonic and adult stem cells
is given by answer choice (B). Embryonic stem cells can
differentiate to become any type of specialized cell, but adult stem cells can only
become certain types of cells.
