10.3 Flashcards
Each of us started life as a single cell, passed through a developmental stage called
an embryo
Differentiation
is the process by which cells become specialized, it determines a cell’s identity.
During the development of an organism, cells differentiate to
become
specialized
scientists use the term totipotent to describe the zygote. The term literally means
“can do everything.”
After four days of development, a human embryo forms into a
blastocyst, a hollow ball of cells with a cluster of cells inside known as inner cell mass ( which are pluripotent).
What Are Stem Cells?
Stem cells are the unspecialized cells from which differentiated cells develop.
Totipotent:
can develop into any type of cell in the body (including the cells that make up the extraembryonic membranes and placenta)
Pluripotent:
cells that are capable of developing into most, but not all, of the body’s cell types
These adult stem cells produce cells for tissues such as blood and skin that have a limited life span and must be constantly replaced.
These adult cells are referred
as multipotent stem cells.
multipotent:
limited potential to develop into many different types of differentiated cells but not all cells.
Pluripotent embryonic stem cells are capable of producing
every cell type in the body
How are scientists able to culture embryonic stem cells
scientists are able to culture embryonic stem cells by removing the inner cell mass from blastocysts and growing the cells in a lab.
•Human adult stem cell research is rarely controversial because
of willing donors.
Human embryonic stem cell research is controversial because
for and against involve ethical issues of life and death.
Harvesting embryonic stem cells cause
the destruction of an embryo.
