Stem Cells and Pluripotency (2C) - Bio & Biochem
- What is the potency of a multipotent stem cell?
- Can form multiple related cell types within a specific tissue/lineage. Multipotent cells are tissue-specific, differentiating into various related types within one lineage.
- What is the potency of an oligopotent stem cell?
- Can form a few closely related cell types within a lineage. Oligopotent cells have narrower potential than multipotent, limited to a few related types in a lineage.
- Which germ layer primarily gives rise to the nervous system and epidermis?
- Ectoderm. Ectoderm forms external and neural tissues as the outermost germ layer.
- Identify the potency: a hematopoietic stem cell that forms all blood cell types but not neurons.
- Multipotent. HSCs are multipotent as they produce all blood cells but are restricted to the hematopoietic lineage.
- What are the three germ layers produced by gastrulation?
- Ectoderm, mesoderm, and endoderm. Gastrulation organizes the embryo into germ layers that specify tissue and organ formation.
- Which germ layer primarily gives rise to muscle, bone, blood, and connective tissue?
- Mesoderm. Mesoderm develops into supportive and circulatory systems as the middle germ layer.
- Which option best matches the term: stem cell niche?
- Local microenvironment signals that maintain stemness and regulate division. The niche provides extrinsic cues to preserve stem cell identity and control proliferation versus differentiation.
- What is the primary fate of the trophoblast in early embryonic development?
- Forms extraembryonic tissues, especially much of the placenta. The trophoblast supports embryonic development by forming structures like the placenta for nutrient exchange.
- Which germ layer primarily gives rise to the epithelial lining of the GI and respiratory tracts?
- Endoderm. Endoderm creates internal linings and organs as the innermost germ layer.
- Which transcription factors are classically used to generate iPSCs (Yamanaka factors)?
- Oct4, Sox2, Klf4, and c-Myc. Yamanaka factors activate pluripotency gene networks to dedifferentiate somatic cells.
- Which embryonic stage contains the zygote and early blastomeres that are totipotent?
- Pre-implantation cleavage stage (zygote through early blastomeres). Early embryonic cells before compaction retain totipotency, allowing formation of an entire organism.
- What is the potency of a totipotent cell?
- Can form all embryonic and extraembryonic tissues (entire organism). Totipotent cells have the broadest potential, enabling development of a complete organism including supportive structures.
- Identify the potency: a cell that can form embryo proper plus placenta and other extraembryonic tissues.
- Totipotent. Totipotency encompasses all embryonic and extraembryonic lineages for complete organism development.
- What is an embryonic stem cell (ESC) defined by source and potency?
- Pluripotent cell derived from the inner cell mass of a blastocyst. ESCs are isolated from pre-implantation embryos and retain ability to form all germ layer derivatives.
- What is the key experimental criterion that demonstrates pluripotency in vitro?
- Differentiation into derivatives of ectoderm, mesoderm, and endoderm. In vitro differentiation to all germ layers confirms pluripotent capacity without ethical issues of in vivo tests.
- What is the embryonic structure from which embryonic stem cells are derived?
- Inner cell mass of the blastocyst. The inner cell mass contains pluripotent cells that give rise to the embryo proper.
- What is the definition of a stem cell in terms of self-renewal and differentiation?
- A cell that self-renews and can differentiate into specialized cell types. Stem cells maintain populations through self-renewal while producing differentiated progeny to form or repair tissues.
- What are induced pluripotent stem cells (iPSCs)?
- Somatic cells reprogrammed back to a pluripotent state. iPSCs are created by reprogramming to restore pluripotency, mimicking embryonic stem cells.
- What is an adult (somatic) stem cell defined by typical potency and role?
- Usually multipotent; maintains and repairs specific tissues. Adult stem cells reside in tissues to enable regeneration and homeostasis within specific lineages.
- Identify the potency: a cell that can form neurons, hepatocytes, and cardiomyocytes but not placenta.
- Pluripotent. Pluripotency allows derivation of diverse somatic cells from all germ layers but excludes extraembryonic tissues.
- What is asymmetric division in stem cells?
- One daughter remains a stem cell and the other becomes a differentiating cell. Asymmetric division ensures stem cell maintenance while generating committed progenitors for tissue needs.
- What is the potency of a unipotent stem/progenitor cell?
- Can form one cell type while retaining self-renewal capacity. Unipotent cells self-renew but are restricted to producing only one differentiated cell type.
- What is the definition of potency in stem cell biology?
- The range of cell types a stem cell can generate. Potency classifies stem cells based on their differentiation potential, from totipotent to unipotent.
- What is a progenitor cell in terms of self-renewal compared with a stem cell?
- More lineage-restricted with limited self-renewal capacity. Progenitors are committed precursors with finite divisions, bridging stem cells and differentiated cells.
- What is the potency of a pluripotent cell?
- Can form all three germ layers but not extraembryonic tissues. Pluripotent cells generate all body cell types from the three germ layers but cannot form extraembryonic structures.