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CELL TECHNOLOGYStem Cells
Definition Unspecialized cells that have two defining
properties: 1) the ability to differentiate into other cells 2) the ability to self-regenerate to form
more stem cellsImportance Development Repair of Adult Tissue Cancer
CELL TECHNOLOGYStem Cells
Differentiation Potential Totipotent Cells
Can develop into all cell types Pluripotent Cells
Can develop into cells of the three germ layers (ectoderm, mesoderm, endoderm)
Multipotent CellsCan develop into cells of a few types
Types Zygote: Totipotent Embryonic: Pluripotent Adult: Multipotent
EMBRYONIC STEM CELLS
Definition Inner cell mass within fertilized cells.
Stage of DevelopmentBlastocyst Hollow ball of ~64 cells containing an inner mass and trophoblast.
ImportanceAble to be directed to any type of cell. “Pluripotent”
ADULT (Somatic) STEM CELLS
Definition Tissue specific stem cells (Multipotent)
PurposeReplacement Damaged and injured tissue Continually-replenished cells
TypesBone Bone Marrow Stromal Cells :Bone, Cartilage,Fibers Hematopoietic Stem Cells : Blood Cells
Brain Neural Stem Cells: Neurons, Astrocytes,
Oligodendrocytes
ADULT (Somatic) STEM CELLS
Plasticity (Transdifferentiation)Definition Ability to differentiate into multiple cell types.Examples Hematopoietic Stem Cells
Brain, Muscle (Cardiac and Skeletal), and Liver Cells
Stromal CellsMuscle Cells
Brain CellsBlood and Skeletal Muscle
CANCER STEM CELLS
Teratocarcinomas (Teratomas)Definition
Germ cell tumor with mixed differentiated tissue and undifferentiated tissue
ExampleLeukemia Acute Increased growth in an early stem
cell Chronic Decreased response to death or differentiation in a stem cell
Fundamental Remaining Questions
1) Does one common type of stem cell migrate to different organs and repair tissue or are there multiple types of stem cells?
2) Does every organ have stem cells (some of which have not yet been discovered)?
3) Are the stem cells programmed to divide a finite number of times or do they have unlimited cell proliferation capacity?
CELL TECHNOLOGY
CloningDefinition Duplicating biological materialTypes Reproductive Therapeutic DNA (Recombinant Technology)
REPRODUCTIVE CLONING
DefinitionProduction of an organism that is genetically identical to an original donor.
Pseudo-cloneClone has genetic material from mitochondria.
ProblemsIncompleteness of genomic imprinting
Process Somatic cell nuclear transfer (SCNT)
SOMATIC CELL NUCLEAR TRANSFER
Process1) Remove mammary cell from donor and starve.2) Remove egg cell from a different donor and enucleate.3) Place mammary cell into egg cell.4) Apply a brief shock to cause mammary cell contents to mix with egg cell contents. 5) Allow cell to go through mitosis.6) Implant into a surrogate sheep.
THERAPEUTIC CLONING
DefinitionProducing a blastocyst from a patient’s somatic cells to be used for therapy.
ProcessSomatic Cell Nuclear TransferExtract inner cell mass at blastocystic stageUse cells to grow tissue or organs
ImportanceCells will not be rejected
RECOMBINANT DNA TECHNOLOGY
DefinitionExcising DNA of interest from one genome and inserting it into a foreign genome.
ProcessGenetic Engineering
Biotechnology: Using genetic engineering to create biological systems that produce a
desired product.Importance
Drugs and medicationsGenome enhancement
RECOMBINANT DNA TECHNOLOGY
Steps(1) DNA Isolation
a) Isolate foreign DNA from desired cell. b) Isolate DNA plasmid vector from bacteria. (2) DNA Fragmentation
a)Cut desired gene from foreign DNA using “Restriction enzymes”.
b) Open plasmid using “Restriction enzymes” to form a gap for DNA insertion.
RECOMBINANT DNA TECHNOLOGY
Steps(3) Plasmid Recombination Insert the foreign gene into the gap of the plasmid by complementary base pairing
of the sticky ends and sealing with DNA ligase.
(4) Recombinant Plasmid Uptake Plasmid is taken up by bacteria through transformation.
RECOMBINANT DNA TECHNOLOGY
Steps(5) Plasmid Replication
Bacterial cell is replicated producing desired DNA clones.
(6) Gene Isolation
DNA sequences can be cut from Plasmids and added to other genomes.
Protein ProductionBacteria can be put into a desired environment
to produce desired protein.