Stem Cells

• What is cell differentiation?

  Process where stem cells develop into specialized cells
• What is the role of selective gene expression in cell differentiation?

  It allows unspecialized cells to develop specific functions
• What is the function of xylem vessels in plants?

  Water transport
• What is the developmental order from zygote to infant?

  Zygote → Embryo → Fetus → Infant
• At what stage is the term "fetus" used in human development?

  After 8 weeks of gestation
• How do gradients of signaling molecules influence differentiation?

  They activate specific genes in different embryo regions
• How do external signals affect gene expression regulation?

  They trigger transcription factors to activate or repress genes
• What is self-renewal in stem cells?

  Ability to divide indefinitely while undifferentiated
• What does potency refer to in stem cells?

  Ability to differentiate into various cell types
• Where are plant stem cells located?

  In meristematic tissue
• What is the potency of bone marrow stem cells?

  Multipotent
• What is the function of stem cell niches in adult humans?

  They provide a specialized environment for stem cells
• What do hair follicle stem cells generate?

  Keratinocytes for hair growth
• What differentiates totipotent stem cells from pluripotent stem cells?

  Totipotent can form placental cells; pluripotent cannot
• Where are multipotent stem cells found in adults?

  Bone marrow
• What is the largest type of cell mentioned?

  Striated muscle fibers
• What is the smallest type of cell mentioned?

  Sperm
• What is the significance of the biconcave shape of red blood cells?

  It maximizes surface area-to-volume ratio
• How do neurons adapt structurally for their function?

  They have long axons and dendrites for signal transmission
• What is the importance of surface area-to-volume ratio in cells?

  High SA:V allows efficient material exchange
• How does the surface area-to-volume ratio change with cell size?

  It decreases as cell size increases
• What are the limitations of models used for surface area-to-volume ratio?

  Cells are irregularly shaped and ignore organelles
• What are current uses of stem cell research?

  Bone marrow transplants and skin grafts
• What are potential future applications of stem cell research?

  Regenerating damaged tissues and disease modeling
• What ethical concerns are associated with embryonic stem cells?

  They raise questions about the use of embryos
• What are alternatives to embryonic stem cells?

  Adult stem cells and induced pluripotent stem cells
• What are the advantages and disadvantages of small and large cells?

  Advantages of small cells:

  • High surface area-to-volume ratio for efficient exchange

  
  

  Advantages of large cells:

  • Store more resources
  • Perform specialized functions (e.g., muscle contraction)
• What drives the differentiation process in cells?

  • Gene regulation
  • Environmental signals
• What are the key concepts of surface area-to-volume ratio?

  • Volume controls metabolic demands
  • Surface area controls material exchange
  • High SA:V allows efficient exchange
  • Low SA:V limits exchange, causing dysfunction
• What are the types of stem cells and their characteristics?

  • Totipotent: All cell types + placental cells (early embryo)
  • Pluripotent: Any body cell (excludes placental) (embryonic stem cells)
  • Multipotent: Limited lineages (e.g., blood cells) (bone marrow)
  • Unipotent: One cell type (e.g., keratinocytes) (hair follicles)
• What are the developmental stages of human growth?

  1. Zygote
  2. Embryo (weeks 1–8)
  3. Fetus (after 8 weeks)
  4. Infant
• What are the structural adaptations of specialized cells?

  • Red Blood Cells: Biconcave shape, no nucleus, packed with hemoglobin
  • Neurons: Long axons, dendrites, synaptic terminals
  • Striated Muscle Cells: Multinucleated, contain myofibrils (actin/myosin)
• What are the functions of stem cell niches in adult humans?

  • Provide a specialized environment for stem cells
  • Support self-renewal and differentiation
• What are the formulas for surface area and volume of common shapes?

  • Sphere:
  • Surface Area: $4\pi r^2$
  • Volume: $\frac{4}{3}\pi r^3$
  • Cube:
  • Surface Area: $6s^2$
  • Volume: $s^3$
• What are the implications of surface area-to-volume ratio in cell function?

  • High SA:V enhances nutrient uptake and waste removal
  • Low SA:V can lead to inefficiencies and dysfunction