Stem Cells and Cloning (TEST 3) Flashcards
Cell differentiation
development of cells from the unspecialized embryonic state to their differentiated specific state
Stem Cells
undifferentiated cells capable of giving rise to an infinite amount more of the same type of cell+some other types of cells
Tissue Stem Cells
capable of replenishing cells within certain organs
Embryonic Stem Cells
undifferentiated with ability to become ANY kind of cell
Cells within the blastocyst?
Cells that are undifferentiated early on and thus have capability to become anything (very flexible)
How does MZT development work?
Each half of the embryo controls its own development until the late blastula stage
What does removing cells from developing embryo do to its fate?
Nothing! The embryo will continue to develop just fine
Totipotent
can differentiate into cell type in the body plus the extraembryonic cells (e.g. placenta
Pluripotent
can differentiate into any of the three germ layers: endoderm (interior stomach lining, gastrointestinal tract, the lungs), mesoderm (muscle, bone, blood, urogenital), or ectoderm (epidermal tissues and nervous system).
Multipotent
partially differentiated and commited to forming certain cell types
Unipotent
produces one cell type
2 ways to regulate transcription?
1) Epigenetic factors (methylation)
2 Transcription Factors (promote or inhibit gene exp)
3 Epigenetic regulations of transcriptions?
1) Histone acetylation/deacytylation relaxes or conensing chromatin
2) Methylation of DNA so that it can’t access transcription factors
3) MicroRNA degrading mRNA
What are the three stem cell criteria?
1) must be undifferentiated
2Unlimited self renewal
3)Two types of daughter cells: new stem
cells and committed progenitor cells
How do Tissue stem cells work?
reside in niches of cells
and extracellular matrix (ECM). Signals (open arrows) from the niche maintain stem cells in their state
Local Asymmetry Model
One daughter cell is stem cell while other is progenator cell
Serial Asymmetry Model
Daughter cells sometimes stem cells and sometimes both progenators
Embryonic Stem Cells
Pluripotent The inner cell mass (ICM) of
the mammalian blastocyst gives rise to the embryo proper
Chimera
organism composed of two or more different populations of genetically distinct cells that originated from different zygotes
What is the complementation test for potency?
Cells to be tested (red) are injected into carrier blastocysts, which are then brought to term by foster females.
Morphological and genetic markers reveal the contributions of the test cells, which may form many cell types or the entire organism.
What are the NIH funding rules for embryonic stem cells? (9)
- hESCs derived for in vitro fertilization and are
no longer needed - Voluntary consent from patient
- No cash for embryos
- Decision to donate or not cannot affect quality
of care to patient - Physician responsible for reproductive clinical care and the hESC researcher should not be
the same person - Patient can change their mind
- No hESCs in non-human primate blastocysts
- No research involving breeding animals where
hESCs contribute to the germ line. - No new stem cell lines from discarded embryos or destroying existing embryos
What is the deal with cloned potatos?
Each row of plants is derived from a single
protoplast grown into a plant and then propagated asexually.
How does reproductive cloning work?
1) Enucleate
2) Get donor nucleus
3) Renuecleate recipient
Why are mammals hard to clone? (3 reasons)
- In mammals , ~1% of genes are imprinted (silenced) by methylation or other epigenetic mechanisms.
- Imprinting is erased in primordial germ cells and then renewed in sex-specific ways during gametogenesis.
- After fertilization, Mom are Dad’s genomes are united, including their imprinted genes.
Reproductive cloning
Growing a baby in mother uterus
Therapeutic Cloning
manipulating embryonic stem cells or equivalents in vitro for the purpose of cell or organ replacement therapies.
