GBIO 2_WEEK1_Q4

• Reproduction


  The biological process by which "offspring" are produced from their "parent" or parents
• Types of reproduction


  • Asexual
  • Sexual
• Asexual reproduction


  • Does not involve gametes, instead parts of a mature organism may develop to new individuals
  • Offspring is genetically identical to the parent
• Organisms with asexual reproduction


  • Unicellular organisms
  • Hydras
  • Sweet potatoes
• Asexual reproduction - Binary Fission

  1. Separation of the body into two new bodies

  2. Common in single-celled organisms
• Asexual reproduction - Budding


  1. A new organism develops from as an outgrowth from the parent body known as a bud

  2. Once grown, the new organism detaches from the parent body
• Asexual reproduction - Fragmentation


  The parent body breaks into several pieces where each piece grows into a new individual
• Asexual reproduction in plants - Vegetative Reproduction

  A plant part such as stems, leaves, roots or turions are used to reproduce new plants
• Sexual reproduction


  • Involves the fusion of male and female gametes to form a zygote
  • Leads to genetic variability
• Fertilization


  The fusion of male and female gametes to form a zygote
• Animal development


  1. Gametogenesis

  2. Fertilization

  3. Implantation

  4. Gastrulation

  5. Embryonic stage

  6. Fetal stage
• Gametogenesis


  The production of gametes (sperm and egg cells)
• Embryonic stage


  • Formation of 4 membranes that supports, protects, and nourish the embryo (yolk sac, allantois, amnion and chorion)
  • Development of placenta
  • Organ formation
• Fetal stage


  • Organs differentiate further and grow
• Gonadotropin-releasing hormone (GnRH)


  Stimulates the release of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH)
• Follicle-Stimulating Hormone (FSH)


  • In males, causes the testes to produce sperm
  • In females, causes the growth of an ovarian follicle and it causes the follicle cells to secrete estrogen
• Luteinizing Hormone (LH)


  • In males, causes testes to secrete testosterone
  • In females, causes ovulation and it causes to secrete progesterone
• Structure of a flower


  • Stamen (male portion)
  • Carpel/Pistil (female portion)
• Monoecious


  Stamens and pistils occur on separate flowers, but the same plant
• Dioecious


  Staminate and pistillate flowers occur on separate plants
• Angiosperm life cycle


  1. Male gametophyte development

  2. Female gametophyte development

  3. Pollination

  4. Fertilization

  5. Embryo development

  6. Seed germination and growth
• Double fertilization


  • One sperm fuses with the egg, forming a diploid zygote, the future embryo
  • The other sperm fuses with the 2n polar nuclei, forming a triploid cell that will develop into the endosperm
• Plant hormones


  • Auxins
  • Cytokinins
  • Gibberellins
  • Ethylene
  • Abscisic acid
• Auxins


  • Stimulate elongation of cells in stem
  • Control phototropism, gravitropism, thigmotropism
  • Stimulate growth of roots from stem cuttings
  • Suppress growth of lateral buds (apical dominance)
• Cytokinins


  • Stimulate cell division in seeds, roots, young leaves, fruits
  • Delay shedding of leaves
  • Stimulate growth of lateral buds
• Gibberellins


  • Stimulate cell division and elongation in roots, shoots, young leaves
  • Break seed dormancy
• Ethylene


  • Hastens fruit ripening
  • Stimulates shedding of leaves, flowers, and fruits
  • Participates in thigmotropism
• Abscisic acid


  • Inhibits shoot growth and maintains bud dormancy
  • Induces and maintains seed dormancy
  • Stimulate protein storage in seed
  • Stimulates closure of stomata