B2.3 cell specialisation Flashcards
stem cells
undefferentiated cell that can
divide indefinetly to create more stem cells, no limit to number of times stem cells can divide
or
differentiate (change in gene expression either activate or deactivate gene) to become a specialised cell type in a multicellular organism
what are the different catagories for cells
totipotent- can form all cell types
pluripotents- many potentials
multipotent- mutliple potentials
unipotent- only one potential
examples of totipotent cels
zygote + morula
examples of pluripotent cels
blastocyst + embryo (until 8 weeks pregnant)
examples of multipotent cels
foetus (after 8 weeks) + tissue adult stem cells
progenitor cells
examples of unipotent cels
terminalyl differentiated cells
whats induced ploripotent stem cells
reprogram gene expression of some adult stem cells and make them return into a pluripotent stage
explain plants pluripotent stem cells
plant zygote is totipotenet once plant body developed, plants have pluripotent stem cells in regions called meristems, two primary meristems;
-shoot meristem (SAM)
-root meristem (RAM)
responsible for plant longitudinal growth in length, and are located at the tip of stem and roote respectively
whats likely source of spare enmbryos
invitrio fertilisation
at what step do cells lose thier totipotency
once it becomes a blastocyst (morula -> blastocyst)
advantages of using stem cells instead of organ transplant
dont have to wait on donor list , with organ transplant might face rehection, may be cheaper
where are hematopoietic stem cells found
they are cells which make blood cells
only found in bone marrow
explain how genetically identical cells produced from stem cells can have quite different functions
determined by gene expression, which ones are activated or deactivated
how do adult stem cells differn from embryonic stem cells
adult= pluripotent
embryonic= totipotent
advantages of using adult stem cells rather than embryonic stem cells
easier to obtain can use patients own stem cells no immunity problem
explain hematopoietic cells
they are pluripotent
ca form;
myeloid progenitor cells which form;
phagocytes
or
lymphocytes (lymphoid progenitor cell)
