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Stem Cell Notes
IB Biology HL 1Mrs. PetersWinter 2014
What we know…
•There are two main types of cells: Prokaryotes (bacteria) and Eukaryotes (plants and animals)
•Organisms can be unicellular (bacteria) or multicellular (plants and animals)
•Cells can function on their own or together forming tissue, organs, organ systems and organisms.
2.1.8 Differentiation
•The process of becoming a specialized cell
•Muscle Cells
•Nerve Cells
•Liver Cells
•The process can not be reversed; specialized cells can’t become unspecialized.
•All cells can differentiate to form the different types of cells in an organism, all have the same DNA, just certain genes are turned on to designate specific function
2.1.7 Emergent Properties
•Cell differentiation allows for emergent properties in multicellular organisms
•Different cell types interact to allow more complex functions to take place.
•Ex: Nerve cells interact with muscle cells to stimulate movement.
2.1.9 What are Stem Cells?
•Stem cells: cells which have not differentiated
•They have not been assigned a specific job in the organism.
•Stem Cell Characteristics:• Unspecialized
• Divide repeatedly to make large numbers of new cells
• Have a large nucleus relative to the volume of the cytoplasm
www.nas-sites.org
2.1.9 Types of Stem Cells
•Totipotent: (total) able to make any body cell or placenta (only from very early cells of embryo, up to 3 days)
•Pluripotent: able to make any body cell (from day 3 to 14 of an embryo)
•Multipotent: able to make a range of cells within a particular tissue type (after day 14 of an embryo)
• Differentiation determined by age of the cell
www.patentbaristas.com
2.1.9 Where are Stem Cells found?
•Embryonic: from donated fertilized eggs (IVF) or donated eggs fertilized by researchers; or products of somatic cell nuclear transfer (genetically identical to donor nucleus)
• pluripotent cells
• can become most cells and tissues of the body
• easier to culture in lab
• great potential for developing future therapies to cure diseases
• potentially ethically problematicwww.en.wikipedia.org
2.1.9 Where are Stem Cells found?
•Adult: often from tissues or organs; can be from cord blood or bone marrow
•
multipotent cells
•
hard to culture in lab
•
Not as ethically problematic
www.stemcells.nih.gov
2.1.9 How do we get stem cells?
•In Vitro Fertilization (IVF)
•Therapeutic Cloning
•Bone Marrow Transplant
•Umbilical Cord Blood
2.1.10 Therapeutic Uses of Stem Cells
• Spinal Cord Injuries
• Parkinson’s Disease
• Heart Disease
• Alzheimer’s Disease
• Diabetes
• Huntington’s Disease
• Your task: choose one of these or find a different use of stem cells, research how stem cells are being used, what advances have been made, are there any disadvantages? (Outline the therapeutic use: give a brief account or summary)
BIG Picture
• Stem Cells have the capacity to divide (and remain undifferentiated)
• Stem Cells have the ability to differentiate along different pathways
