SUMMATIVE BIO LESSON 2

• Plants are the antennae by which the energy of sunlight is captured in the ecosphere and then stored in food for later slow, catabolic release in the living cells of both plants and animals.
• Two Major Groups Of Seed

  • Gymnosperms
  • Angiosperms
• Gymnosperms


  means “naked seeds” that is based on the unenclosed condition of their seeds)
• Angiosperms


  a plant that has flowers and produces seeds enclosed within a carpel.
• Seed Coat


  In a typical monocot such as a grass, the seed is surrounded with a protective _____.
• Aleurone Layer


  lies under the seed coat, functions as a kind of digestive organ in seed germination.
• Endosperm


  a food storage tissue that forms separately from the embryo while the seed is still attached to the parent plant.
• Coleorhiza


  protects the future root or (radicle).
• Scutellum


  In grass embryos, a very large cotyledon develops, which is known as the _______.
• Monocot


  means “single leaf,” which refers to its only seed structure that appears to be homologous with a leaf – the single cotyledon.
• Dicots


  have two cotyledons.
• Plumule


  corresponds to the shoot apex in monocots.
• Suspensor


  From the basal cell develops a filament of cells called a ______.
• Hypocotyl , Epicotyl


  In dicots, the part of the axis below the point of attachment of the cotyledons is called the ______ and the part above it, is the ______.
• Dormancy


  The embryonic plant is kept in a state of suspended development called ______, which ends when germination takes place.
• Gibberellin


  As a first step in breaking dormancy, the embryo emits a hormone called ______, which diffuses through the seed.
• apical meristem


  a growing tip of embryonic, differentiating tissue.
• zone of elongation


  responsible for most of the lengthwise growth of the root tip.
• Zone of Division


  The actual living tissue, however, is undergoing vigorous mitosis. For that reason, this part of the root tip is known as the ________.
• zone of maturation


  tissue differentiation now begins.
• primary meristems


  give rise to differentiated tissues such as phloem and xylem.
• Leaf Growth


  Each leaf originates on the side of the meristem, growing upward as it enlarges and begins to differentiate. Once its growth is well under way, another group of cells next to it and somewhat above it begins to grow outward and upward.
• Leaf Fall


  Leaves age and die in all plants, and in some cases the plant senesces as a whole. As xylem ages, for example, it becomes clogged with resins and turns to heartwood. As cells produced by the cork cambium age, they die and become converted to cork.
• The Ecology of Abscission 


  Abscission is the process by which plants shed one of their parts, and an abscission layer is an adaptation that specifically permits loss of leaves. The abscission layer also represents a point of weakness, so that in due time, the yellowed leaves are swirled away by the winds of winter.
• Provascular Cylinder


  In the center of the apical bud is a cylinder that develops into the vascular tissues as it matures.
• Protoderm 


  potential epidermis that can develops on the exterior of apical bud.
• ground meristem or ground tissue


  becomes the cortex and the pith.
• primary thickening meristem


  is derived from the apical meristem, which continuously enlarges to produce it.
• zygote 


  is a fertilized egg that has the potential to give rise to all the diverse cell types of the complete individual.
• yolk


  serves as food for the developing embryo.
• Cleavage


  a process wherein the zygote undergoes a rapid mitosis.
• Morula


  tiny cluster of cells.
• The Blastocyst 


  During this period, its cells arrange themselves into the form of hollow ball called blastocyst (blastula), eventually forms and nutritive membranes (the chorion and placenta) that surround the embryo.
• inner cell mass


  projects into the cavity of the blastocyst. These cells give rise to the embryo itself.
• Implantation of embryo in the endometrium (lining) of the uterus begins on the seventh day of embryonic development. During this period, enzymes destroy some tiny maternal capillaries in the wall of the uterus.
• 3 germ layers produced by inner cell mass

  • Ectoderm
  • Mesoderm
  • Endoderm
• 9 stages of human cycle

  1. embryo
  2. fetus
  3. Neonate
  4. Infant
  5. Child
  6. Adolescent
  7. Young Adult
  8. Middle Age
  9. Old Age