4Cell DeterminationCELL DETERMINATION is the process by which portions of the genome are selected for expression in different embryonic cells. This involves developmental decisions that gradually restrict cell fate. Cells can progress from TOTIPOTENT to PLURIPOTENT to DETERMINED.
5Animal cell undergoes simillar early embryonic development From Egg To Tadpole nextBlastula nextGastrulation nextHuamn embryo development next
6A cell can be determined long before it show any obervious outwad sign of differentiation Gastrula Endoderm,Mesoderm,EctodermnextEmbryo Transplation nextMisplaced tissue next
7How do two cells with the same genome come to be different? Sister cells can be born different by an asymmetric cell division nextCell-to-cell interaction in cell fate determination nextEmbryonic Induction next
8Housekeeping geneHousekeeping Gene serving a fuction required in all the cell types of an organism, regardless of their specialized role.
9luxury geneLuxury gene Gene performing specialized function in a definite type of cell, not required by all cell types of an organism.
10Cell Differentiation Differentiation – The process whereby an unspecialized early embryonic cellacquires the features of a specializedcell such as a heart, liver, or musclecell.
11Differentiated Cell Remain Totipotent Cloning of animal by nulear transfer
12Principle of Cell Differentiation Each differentiated cell contains a complete genome.The differences between different types of cells are only duo to expression of different kinds of proteins, that is, a set of genes are switched on in a certain type of cell, meanwhile are switched off in another type of cell.
13Cell differentiation is controlled by Transcription Tissue specific transcription factors These proteins cause the experssion of a whole block of proteins that together give cell its identity.
15Cell Differentiation is reversible Embryonic Stem cell (ES) can complete the whole process of differentiation in proper environment.nextDifferentiated cell can undergo dedifferentiation or transdifferentiation.Cancer cell can be induce to differentiate.next
16Stem Cell WHAT ARE THE UNIQUE PROPERTIES OF ALL STEM CELLS? next WHAT ARE EMBRYONIC STEM CELLS? nextWHAT ARE ADULT STEM CELLS? extOBSTACLES THAT MUST BE OVERCOME next
17All stem cells have three general properties Stem cells are capable of dividing and renewing themselves for long periods.Stem cells are unspecialized.Stem cells can give rise to specialized cells.continue
18WHAT ARE EMBRYONIC STEM CELLS? Embryonic stem cells – Primitive (undifferentiated) cells from the embryo that have the potential to become a wide variety of specialized cell types.Human embryonic stem cells are derived from blastocystnext
19Diseases that might be treated by ES cells Diseases that might be treated by transplanting cells generated from human embryonic stem cells include Parkinson’s disease, diabetes, traumatic spinal cord injury, Purkinje cell degeneration, Duchenne’s muscular dystrophy, heart disease, and vision and hearing loss. next
20How are embryonic stem cells stimulated to differentiate?
21How are embryonic stem cells stimulated to differentiate? continued
22WHAT ARE ADULT STEM CELLS? Adult stem cell–An undifferentiated cell found in a differentiated tissue that can renew itself and (with certain limitations) differentiate to yield all the specialized cell types of the tissue from which it originated.next
24OBSTACLES THAT MUST BE OVERCOME Proliferate extensively and generate sufficient quantities of tissue.Differentiate into the desired cell type(s).Survive in the recipient after transplant.
25OBSTACLES THAT MUST BE OVERCOME continued Integrate into the surrounding tissue after transplant.Function appropriately for the duration of the recipient’s life.Avoid harming the recipient in any way.
53Asymmetric division are particularly common at the beginning of development, when the fertilized egg divides to give daughter cells with different fates,but they also occur at later stages—in the genesis of nerbe cells,for example.next
54Asymmetric division segregating P granules into the founder cel of the C.elegans germ line.
56The linegae tree for the cells that form the gut of C.elegans.
57The pattern of the cell divisions in the early nematode embryo.
58Cell-signal path ways controlling assignment of different characters to the cells in a four-cell nematode embryo.
59Vertebrate embryos rely extensively upon inductive interactions to diversify the number of different kinds of cells in the embryo.next
60Induction is the process by which one group of cells produces a signal that determines the fate of a second group of cells.
61This implies both the capacity to produce a signal (ligand) by the inducing cells and the competence of the responding cells to receive and interpret the signal via a signal transduction pathway.The chemical characterist of inducer is protein.
62The presence of organizing centers—the Mangold–Spemann experiment.a
63The presence of organizing centers—the Mangold–Spemann experiment.b