Bio 93 Lecture 24

  1. The fate of cells in the embryo is determined by:
    cytoplasmic determinants
  2. What generates lots of small undifferentiated cells?
    cleavage
  3. A ____________ gives rise to cells of many different types, each with a different structure and corresponding function
    single-celled zygote
  4. What does a program of differential gene expression lead to?
    the different cell types in a multicellular organism
  5. During embryonic development, a fertilized egg gives rise to:
    many different cell types
  6. Cell types are organized successively into:
    tissues, organs, organ systems, and the whole organism
  7. What orchestrates the developmental programs for animals?
    gene expression
  8. The transformation from zygote to adult results from:
    cell division, cell differentiation, and morphogenesis
  9. What is cell differentiation?
    the process by which cells become specialized in structure and function
  10. The physical processes that give an organism its shape constitute
    morphogenesis
  11. Differential gene expression results from
    genes being regulated differently in each cell type
  12. What are cytoplasmic determinants?
    maternal substances in the egg that influence early development
  13. Explain what leads to different gene expression:
    as the zygote divides by mitosis, cells contain different cytoplasmic determinants
  14. What is induction?
    • a process in which signal molecules from embryonic cells cause transcriptional changes to nearby target cells
    • in other words, switch on genes in nearby cells
  15. What is determination and when does it occur?
    • determination proceeds differentiation and it commits a cell to its final fate.
    • after determination, the cell fully becomes a specialized cell
  16. What do myoblasts produce and form?
    muscle-specific proteins and form skeletal muscle cells
  17. What is one example of a "master regulatory genes" that produce proteins that commit the cell to becoming skeletal muscle?
    MyoD
  18. What is MyoD protein?
    a transcription factor that binds to enhancers of various target genes
  19. What is pattern formation?
    the development of a spatial organization of tissues and organs
  20. In animals, pattern formation usually begins with the establishment of the:
    major axis
  21. What do maternal genes encode for?
    for cytoplasmic determinants that initially establish the axis of the body of drosophila
  22. What maximum recombination frequency would be observed if the two genes are on separate chromosomes?
    50%
  23. What recombination frequency would be observed if two genes are on the same chromosome and they are so close together that a crossing over event is impossible?
    0%
  24. Are all genes genomically imprinted?
    No, only a small subset of genes are genomically imprinted. It is estimated that only approximately 1% of genes may be imprinted.
  25. What is responsible for most cases of Beckwith-Wiedemann syndrome?
    genomic imprinting
  26. What is a bicoid?
    a morphogen determining head structures
  27. An embryo whose mother has no functional bicoid gene lacks:
    the front half of its body and has duplicate posterior structures at both ends
  28. The bicoid research is important for three reasons:
    • it identified a specific protein required for some early steps in pattern formation
    • it increased understanding of the mother's role in embryo development
    • it demonstrated a key developmental principle that a gradient of molecules can determine polarity and position in the embryo
  29. What are the four stages of embryonic development?
    • fertilization
    • cleavage
    • gastrulation
    • organogenesis
  30. Define fertilization:
    combination of sperm and egg nuclei and egg activation; haploid to diploid
  31. Define cleavage:
    rapid cell divisions without substantial; growth in size to generate a multicellular embryo
  32. Define gastrulation:
    mass cell movements to generate three germ layers
  33. Define Organogenesis:
    localized changes in tissue and cell shape
  34. What are blastomeres?
    cleavage partitions the cytoplasm of one large cell into many smaller cells
  35. What is the blastula?
    a ball of cells with a fluid-filled cavity called a blastocoel
  36. In frogs and many other animals, what is a key factor influencing the pattern of cleavage?
    the distribution of yolk
  37. The ____ pole has more yolk; the _____ pole has less yolk
    vegetal, animal
  38. What does the difference in yolk distribution result in?
    animal and vegetal hemispheres that differ in appearance
  39. When do animal embryos complete cleavage?
    when the ratio of material in the nucleus relative to the cytoplasm is sufficiently large
  40. Morphogenesis in animals involves specific changes in:
    cell shape, position, and survival
  41. What is morphogenesis? What does it involve?
    • the process by which cells occupy their appropriate locations
    • gastrulation and organogenesis
  42. What is gastrulation?
    the movement of cells from the blastula surface to the interior of the embryo
  43. What is organogenesis?
    the formation of organs
  44. Where is the ectoderm and what does it make?
    • outer layer of embryo
    • sweat glands, hair follicles, nervous and sensory systems, pituitary gland, adrenal medulla, jaws, teeth, and germ cells
  45. Where is the mesoderm and what does it make?
    • middle layer of embryo
    • skeletal and muscular systems, circulatory and lymphatic systems, excretory and reproductive systems (except germ cells), dermis of skin, and adrenal cortex
  46. Where is the endoderm and what does it make?
    • inner later of embryo
    • epithelial lining of digestive tract and associated organs (liver and pancreas), epithelial lining of respiratory, excretory, and reproductive tracts and ducts, thymus, thyroid, and parathyroid glands
  47. During _______, various regions of the germ layers develop into rudimentary organs
    organogenesis
  48. Early in vertebrae organogenesis, the ______ forms from mesoderm, and the _________ forms from ectoderm
    notochord, ectoderm
  49. The neural plate soon curves inward, forming the _________
    neural tube
  50. The neural tube will become:
    the central nervous system (brain and spine)
  51. ____________ develop along the neural tube of vertebrates and form various parts of the embryo (nerves, parts of teeth, skull bones, and so on)
    neural crest cells
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jocelyn0399
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Bio 93 Lecture 24
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