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53 Cards in this Set
- Front
- Back
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Totipotent stem cells
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**produced from the fusion of an egg and sperm cell
**able to differentiate into all tissue and a placenta *zygote up to the morula stage are also totipotent--- differentiate into embryonic and extraembryonic cell types |
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Pluripotent stem cells
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**descendandts of totipotent cells
**orginate as inner mass cells w/in blastocysts **can differentiate/become any tissue in the body, except placenta |
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three types of pluripotent stem cells have been found: (cells that we can get pluripotent stem cells)
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1. Embryonic Stem (ES) cells
2. Embryonic Germ (EG) Cells 3. Embryonic Carcinoma (EC) cells |
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Embryonic Stem (ES) cell
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inner cell mass (ICM)
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Embryonic Germ (GG) Cells
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isolated from the precursor to the gonad in aborted fetuses (precursor stem cell for spermatogonium and oogonia)
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Embryonic Carcinoma (EC) Cells
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fetal gonad tumors
**they are aneuploid |
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3. Multipotem stem cells
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**restricted/limited tissue differentiation
**mostly adult stem cells e.g bone marrow stem cells ---->becoming WBC and RBC **advangtage of this is that you get it from an adult |
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4. Unipoten stem cell
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**cells can produce only one cell type, but have the property of self-renewal
e.g bone marrow stem cell ---> lymphoid stem cells---> only lymphocytes |
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Pluripotent stem cells (most popular). How do you make it?
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Use in vitro fertilzation
in vitro fertilization--->--->8 cell stage---> blastocysts--->take out inner cell mass--> grow them in culture--->give them signal--->cell differentiate into cell types (e.g nerve cell)---> put to patient |
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what are some (3) approaches to get pluripotent stem cells?
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1. Take an 8 cell morula
2. Somatic nuclear transfer 3. Differentiate cell form a mouse |
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1. take an 8 cell morula
**process |
take 8 cell morula--->take out one cell---> put in vitro---> make new blastocyst---> source for stem cells
**take the other sevens to make a fetus |
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2. Somatic nuclear transfer
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**work in primate have not been seen in human
take a pimary oocyte---> get rid of the nucleus (nucleated)---> give another diploid nucleus (e.g somatic cells--skin)---> get stem cells **problem w/ ploidy |
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3. differentiate cell from a mouse
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example: experiment done on mouse only
skin cell---> turn into "signals---> genes ---> stem cell-like property |
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[FROG DEVELOPMENT]
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**cleavage partitioning of the cytoplasm
**gastrulation **Organogenesis-- rudimentory ogans |
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frog eggs has two pole
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**animal pole
**vegetal pole--- yolk; heavier; polarity is here |
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the protein inside the frog eggs are _____
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heterogenous distribution
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what does heterogenous distribution means
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chromosomes xy and ab are always the same if you partition the cytoplasm
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[frong] fertilization is only successful in _____. which pole?
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animal pole
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Fertilzation-- you have a wave of Ca++ that causes the _____
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plama membrane cortex (an outer membrane)
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the PM cortex will move to where fertilization first take place thus your able to see _______
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the grey crescent--- a non-pigmented region of the fertilize egg
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Why is the gray crescent important?
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**the protein underneath the Grey Cresscent is determinant for polarity----> detect dorsal polarity
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Thus if you take this dorsal polarity out what does the embryo features end up being like?
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you'll only be able to see the belly **dorsal plane is gone
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what is the differences b/w human and frog reproduction (after fertilization)?
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**Human
-cleavage plane = Hemogenous (random, not in a plane) -blastocyst = implant **Frog -cleavage plane = heterogeneous (specific cleavage plane, horizontal) -blastula = out in the water |
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What type of cleavage plane does a each of these posses from a zygote---> morula
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zygote---> 2-cells (ventricle)----> 8-cells (ventricle) ----> morula stage (horizontal)
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After Blastula is gastrulation-- formation of the 3 germ layer embryo. What drive this?
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cell embryo movement and cell-cell binding drive this
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Bird has a _____ instead of a blastopore
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primative streak
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In the blastocyst, the inner cell mass-- Epiblast and Hypoblast turn into what part of the germ layer?
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Epiblast---> ectoderm, mesoderm, endoderm (day 13-14)
Hypoblast (yolk sack)---> blood cell |
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which side proliferate faster? the animal or vegital pole
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animal pole
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After gastrulation is _____
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organogenesis
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[ORGANOGENESIS] what is organogenesis
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formation of Rudimentary (earliest state of development) Organs
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what drive the process of organogenesis?
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*cell movement, cell shape, cell-cell interaction
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[Cell shape] what regulate cleavage?
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Changes in cell shape and position
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_____ changes drive shape of cells
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cytoskeleton
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how do cells change shape?
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by wedging--- cells become wider
**this controls lots processes, in particular neural tube formation |
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describe the process of neural tube formation
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start w/ cell layer---> start wedging---> eventually it comes together and break off.
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What is another process that can drive organogenesis (part of cell shape)?
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convergent extension
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what is convergent extension?
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sheets of cells become narrower (converges) and longer (extend)
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How do cells know where to go?
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**directional cues = positive and negative directional cues
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[hormonal control mechanism] what is inductive signal
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**drive differentiation and pattern formation of vertebrates
**"hormone-like" signals produced by one group of cells that alters the gene expression pattern |
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There are two types of inductive signals:
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negative and positive inductive signals
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Give an example of positive signal:
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two circle cells (no signal)---> give them positive signals----> becomes circle and square
**inorder to keep the square you need positive signal |
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Conversely, inductive negative signals (does what?)
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**inductive negative signals can over ride an inductive positive signals
**for example: two cells can maintain circular form b/c of a + signal, but if its given a negative signal one of the cell become a square **signal is needed to keep a process going or stop the process |
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what is an example of inductive positive and negative signals we talked in lecture?
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Dorsal lip of the blastopore (Spelmann's organizer)
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[spelmann's organizer] in the blastula (frog egg), what signals produces the ventral (belly)?
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ventral produce positive signals called BMP-4 (bone morphogenic protine -4)
*which binds to a receptor to give ventral belly |
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Dorsal signal is called ____
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Noggin (negative signals)
**binds to BMP-4 ---> as a result BMP-4 cannot find its receptors----> Noggin overrides BMP-4 **thus structure is dorsal |
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Give an example of positive inductive signal
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Zone of polarizing activity (ZPA)
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what is ZPA? what happens when you have extra ZPA
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a major limb bud organizer
**when you have extra ZPA, gives rise to posterior ploidity---> extra digits in fingers |
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Conversely, inductive negative signals (does what?)
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**inductive negative signals can over ride an inductive positive signals
**for example: two cells can maintain circular form b/c of a + signal, but if its given a negative signal one of the cell become a square **signal is needed to keep a process going or stop the process |
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what is an example of inductive positive and negative signals we talked in lecture?
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Dorsal lip of the blastopore (Spelmann's organizer)
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[spelmann's organizer] in the blastula (frog egg), what signals produces the ventral (belly)?
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ventral produce positive signals called BMP-4 (bone morphogenic protine -4)
*which binds to a receptor to give ventral belly |
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Dorsal signal is called ____
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Noggin (negative signals)
**binds to BMP-4 ---> as a result BMP-4 cannot find its receptors----> Noggin overrides BMP-4 **thus structure is dorsal |
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Give an example of positive inductive signal
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Zone of polarizing activity (ZPA)
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what is ZPA? what happens when you have extra ZPA
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a major limb bud organizer
**when you have extra ZPA, gives rise to posterior ploidity---> extra digits in fingers |
