2.6 Stem Cells Flashcards
what are stem cells?
unspecialised cells that can divide by mitosis and potentially differentiate into any type of cell during development
give examples of where stem cells can be found:
embryos
umbilical cords
bone marrow
what is potency?
a stem cells ability to differentiate into different cell types
the more cells it can differentiate into the greater it’s potency
what are totipotent stem cells?
can differentiate into any type of cell they have the potential to form a whole organism
what are pluripotent stem cells?
can form all tissue types but not whole organisms
what are multipotent stem cells?
only form a range of cells within a certain type of tissue
how do cells become specialised?
certain genes are expressed, the rest are switched off
where are totipotent stem cells found?
zygotes
after 7 days a blastocyst forms and the stem cells become what?
pluripotent
when are tissue stem cells present?
from birth
give an example of where tissue stem cells are found:
bone marrow
tissue stem cells are what type of stem cell?
multipotent
give examples of where multipotent adult stem cells can be found:
liver pancreas umbilical cord spinal cord bone marrow skin blood
adult stem cells are multipotent and can be triggered to become what?
pluripotent
why are stem cells found in umbilical cords useful for research?
in plentiful supply
non invasive
can be stored
where is plant meristematic tissue found?
tips of roots and shoots where growth is occurring
between xylem and phloem - known as vascular cambium
what can cells from the vascular cambium do?
differentiate into xylem and phloem
what is the potency of the plant stem cells?
pluripotent (remain pluripotent throughout a plants life)
what is a RBCs average life span and why?
120 days
lack of organelles & nucleus (akaryotic)
stem cells in the bone marrow produce how many RBCs per kg of body mass per day?
3 billion