[CJC] Stem Cells (1.5) Lecture Notes

Page 1 | 20 CATHOLIC JUNIOR COLLEGE H2 Biology JC1 CORE IDEA 1] THE CELL AND BIOMOLECULES OF LIFE 1.5 STEM CELLS Narrative from H2 Biology 9744 Syllabus: This concept highlights the diversity in cell type and morphology in an organism. In an organism, all cells except the gametes are genetically identical. Yet, a liver cell, a rod cell in the eye and an epithelial cell in the ileum differ significantly in terms of morphology and function due to differential gene expression. The same genome gives rise to a wide range of cells which further forms tissues, organs and systems in an organism. The ability of stem cells to divide and their potential for self -renewal allows growth. Stem cells replace cells that die or are damaged. During embryogenesis, cell division and differentiation allow the development of an entire organism in utero from a single-cell zygote. Stem cells hold great potential as medical treatments. Haematopoietic stem cells are used in blood marrow transplants in cancer treatments. Skin stem cells may be used to culture skin cells to treat patients with massive burns. Ethical debates over the use of stem cells are primarily concerned with the use of embryonic stem cells. Use of adult stem cells faces fewer of such ethical issues. Candidates should be able to: Subtopic Learning Outcomes UNIQUE FEATURES OF STEM CELLS 1(t) Describe the unique features of stem cells , including zygotic stem cells, embryonic stem cells and blood stem cells (lymphoid and myeloid), correctly using the terms: i. totipotency (e.g. zygotic stem cells which have ability to differentiate into ANY cell type to form whole organisms and so are also pluripotent and multipotent), ii. pluripotency (e.g. embryonic stem cells which have ability to differentiate into ALMOST any cell type to form any organ and so are not totipotent but are multipotent) and iii. multipotency (e.g. lymphoid and myeloid stem cells which have ability to differentiate into a LIMITED range of cell type and so are not pluripotent or totipotent) NORMAL FUNCTIONS OF STEM CELLS 1(u) Explain the normal functions of stem cells in a living organism , including embryonic stem cells and blood stem cells (lymphoid and myeloid stem cells) ETHICAL IMPLICATIONS OF STEM CELL APPLICATIONS 1(v) Discuss the ethical implications of the application of stem cells in research and medical applications and how human induced pluripotent stem cells (iPSCs) overcome some of these issues. (Procedural details of how iPSCs are formed are NOT required.) CONTENT PAGE Concept Map 2 1 UNIQUE FEATURES of STEM CELLS 3 – 6 1.1 Unique Features of ALL Stem Cells 3 1.2 Development Potential of Stem Cells 1.2.1 Totipotency (e.g. zygotic stem cells) 1.2.2 Pluripotency (e.g. embryonic stem cells) 1.2.3 Multipotency (e.g. adult stem cells) 4 5 6 2 NORMAL FUNCTIONS of STEM CELLS 7 – 9 2.1 Embryonic