Biology

• Plants


  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
• Gymnosperms and Angiosperms


  The two major groups of seed plants
• Gymnosperms


  • Both male and female reproductive organs
  • Includes conifers, cycads, Ginkgo, and gnetophytes
• Gymnosperm


  Means "naked seeds" based on the unenclosed condition of their seeds
• Angiosperms


  • Have flowers and produce seeds enclosed within a carpel
  • A large group including herbaceous plants, shrubs, grasses, and most trees
• Monocots and dicots


  The two divisions of angiosperms, mostly based on their seed structure
• Monocot seed


  • Surrounded by a protective seed coat
  • Has an aleurone layer that functions as a digestive organ in seed germination
  • Mostly consists of starchy endosperm, a food storage tissue
• Monocot


  Means "single leaf", referring to the single cotyledon
• Scutellum


  A very large cotyledon in grass embryos
• Dicot seed

  • Has two cotyledons
  • Includes the radicle and plumule
• Embryo and cotyledon(s) formation

  1. Result of two distinct fertilizations

  2. Basal cell develops into a filament called suspensor
• hypocotyl

  • The part below the cotyledons
• Dormancy

  The state of suspended development the embryonic plant is kept in, ending with germination
• Breaking dormancy


  Embryo emits gibberellin hormone that diffuses through the seed
• Leaf growth


  1. Originates on the side of the meristem, growing upward as it enlarges and differentiates

  2. Another group of cells next to and above it begins to grow outward and upward
• Leaf fall


  Leaves age and die, xylem ages and turns to heartwood, cork cambium cells age and become converted to cork
• Abscission


  • The process by which plants shed one of their parts
• Zygote

  A fertilized egg with the potential to give rise to all cell types of the complete individual
• Implantation

  1. Begins on 7th day, enzymes destroy maternal capillaries in uterus wall

  2. Completed by 9th day
• Stages of life

  • Embryo (conception to 8 weeks)
  • Fetus (9 weeks to birth)
  • Neonate (birth to 4 weeks)
  • Infant (4 weeks to 2 years)
  • Child (2 years to puberty)
  • Adolescent (puberty to 14 years)
  • Young adult (end of adolescence)
  • Middle age (40 to 65 years)
  • Old age (65 to death)
• Early development


  • Zygote
  • Cleavage
  • Blastocyst
  • Implantation
  • Formation of germ layers
• Types of seed plants


  • Monocot
  • Dicot
• Glucose - contains the elements carbon, oxygen, and hydrogen, the only elements occurring in complex sugars and in most fats.
• Nutrient – refers to any substance required for the growth and maintenance of an organism.
• autotrophs – organisms that obtain energy from sunlight and chemicals to produce their own food.
• heterotrophs – organisms that cannot make their own food and obtain their energy from other organism
• Autotrophs and heterotrophs - The two types of organisms based on the mode of nutrition
• Macronutrients - are those nutrients needed by all plants in relatively large amounts.
• Nitrogen - was one of the first nutrients to be discovered. Although it can be provided in the form of nitrate or ammonia, it is usually absorbed in the form of nitrate.
• Nitrogen - is needed for proper leaf growth and development
• Potassium - another early known plant nutrient, is traditionally added to the soil in the form of wood ash.
• Phosphorus - essential for the production of such vital compounds as the nucleic acids and ATP
• Sulfur - is an essential component of protein because of its occurrence in the amino acids cysteine and methionine.
• Calcium - is an important component of the middle lamella of cell walls
• Magnesium - is required for the action of many enzymes and is needed also in the synthesis of chlorophyll, which contains it.
• Micronutrients - are as vital as macronutrients but are required only in extremely small amounts.
• Iron - is needed in several of the electron transport substances of the cell (ferredoxin, cytochromes), and in some other materials (e.g., phytochrome).
• Boron - The function of it is unknown. Deficiency results in abnormally dark foliage, growth abnormalities, and malformations
• Zinc - is required for the production of amino acid tryptophan.
• Manganese - is required as a cofactor for enzymes in oxidative metabolism and in photosynthetic oxygen production