stem cells and totipotency Flashcards
what is differentiation
when cells develop into specialised cell structures
how do single cell organism carry out function
one cell carries out all the functions adequately but cannot carry one out efficiently
what are the cells in multicellular organisms
they are adapted to carry out specific roles and functions
how do multicellular organisms start off
a tiny ball- zygote of identical cells
what happens as the cell starts to differentiate
dvelop individual characteristics that allow them to carry out function efficiently
what do all cells contain and why
they all contain the same genes as they start to mitotically divide of the zygote
so what does this mean in terms of capability
all cells are capable of making every protien in the body
so why arent all the protiens produced by every cell
only certain genes are expressed in only one cell at a time
what genes are permanely expressed in all cells
such as enzymes for repiration, transcription and translation of protien ass all cells carry out these process
why are differentiated cells different visibly
they produce different protiens as a result of the different genes expression which causes them to look different
what is totipotent
when s cell can develop into any body cell such as a zygote and later become differentiated
so har are the specified protiens made
only the section of dna for a particular polypeptide is translated and transcripted to make the desired gne
what can they do but dont do
they can stimulate other protiens but doing so would be wasteful
how do you activate the other protiens
enable transcription and translation
what is the limitation of specialised cells
their differentiation is usually irreversible eg red blood cells
what are stem cells
undifferentiated cells that have the ability to mature and differentiate into other cells
what is special about stem cells
occur in a adult cells and constantly dividing and make identical copies of themselves -self renewal
where do they come from
embryonic stem cell
umbilical cord
plasma stem cells
adult stem cells
what are embryonic stem cells
they come from embryos in early stage of development and can differentiate into any cell
what are adult stem cells
found in featus and continue to find in adult TISSUES they are specific to a tissue or organ and replace the damaged cell or repair through self renewal
what is totipotent
found in zygote can differentiate into any cell, usually only slightly develop into a more specialised cell like a pluropotent
what is pluripotent
found in embryos and can differentiate into nearly almost any type of cell and form more specialised multipotent
what is multipotent
found in adult stem cells usually differentiate to limited particular UNIPOTENT type of cells eg blood marrow to blood cells develop into unipotent
what is unipotent stem cells
any body cell can only differentiate into one type of cell made in adult tissue
what is an induced pluripotent stem cell
type of pluripotent cells formed from unipotent cells
what happens to these unipotent stem cells
they are genetically altered and we add transcription facotr to induce genes
what does this do
turn gene on which were turned off
what is special about ips
they are very simmilair to embryonic stem cell and can almost differentiate into any cell
however what are the differences
they may be made from different material , and also can divide indefinately as they are self renewal
what is a strength of using ips
no need to use embryos so maneuvere the ethics
can help treat disease a
what are the weakness
they have the potential to also cause disease
why do we prefer to use zygote and embryonic in research
as they have the greatest potential to differentiate into any cells and treat disease
how are the cells obtained
the extra embryos that are left over after ivf treatment
when is such research allowed
only under strict condition in attempt to treat diseases
what is done to the embryos
they are cultured in nutrients which causes the inernal mass to be released
what happens to this mass
chemicals are added which breaks the mass up into smaller groups
what happens to the groups
they are grown in colonies of embryonic stem cell and then added differentiated factors
what do people consider about using human embryos
they arent human before the age of 14 dyas
however we shouldnt make an embryo suffer for no reason
its just a ball of cells
