Exam Notes BIO

• Sporophytic generation


  Diploid generation
• Gametophytic generation


  Haploid generation
• Sporophytic generation


  1. Produces spores through meiosis, halving the chromosome number

  2. Spores develop into gametophytes
• Gametophytic generation


  1. Produces gametes (eggs and sperm) through mitosis, maintaining the chromosome number

  2. Gametes fuse during fertilization to form a zygote (diploid)

  3. The zygote develops into a new sporophyte, completing the cycle
• Flowering plants (angiosperms)


  • Reduced gametophyte lives within the flower
• Cone-bearing plants (gymnosperms)


  • Gametophytes develop into free-living structures
• Sporophyte


  Diploid stage
• Gametophyte


  Haploid stage
• Meiosis


  Forms haploid spores
• Mitosis


  Forms haploid gametes
• Fertilization


  1. Fusion of a sperm cell (male gamete) with an egg cell (female gamete) forms a zygote

  2. Restores the diploid chromosome number in the resulting zygote

  3. Initiates embryonic development
• Stages of Embryonic Development

  • Germinal: 0-2 weeks
  • Embryonic: 3-8 weeks
  • Fetal: 9 weeks to birth
• Essential materials for plants

  • Macronutrients
  • Micronutrients
• Primary Macronutrients


  • Nitrogen: Essential for plant growth, forms proteins, nucleic acids, and chlorophyll
  • Phosphorus: Important for energy transfer and structural development
  • Potassium: Regulates plant processes, enhances disease resistance
• Other Macronutrients


  • Hydrogen and Oxygen: Essential for photosynthesis and cellular respiration
  • Carbon: Forms essential compounds like carbohydrates, proteins, and nucleic acids
  • Sulfur: Required for protein synthesis, chlorophyll production, and enzyme activation
  • Calcium: Regulates nutrient transport, supports enzyme functions, and maintains structural integrity
  • Magnesium: Essential for ionic balance, chlorophyll synthesis, and DNA/RNA synthesis
• Xylem


  Transport water and nutrients from roots to other plant parts via tracheids and vessels
• Phloem


  Transport nutrients and food from roots to other growing parts of plants
• Movement of Materials in Vascular Tissues

  1. Absorption: Collection of water and nutrients from the soil through roots

  2. Cohesion: Ability of water to flow through narrow spaces in xylem and phloem

  3. Transpiration: Loss of water through stems and leaves
• Importance of Elemental Nutrients

  • Carbon
  • Boron
  • Nitrogen
  • Potassium
  • Hydrogen and Oxygen
• Macronutrients are needed in larger amounts, including carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur
• Micronutrients are required in smaller amounts, such as boron, chlorine, manganese, iron, zinc, copper, and molybdenum
• Deficiency of these nutrients can adversely affect plant health
• Vascular tissues (xylem and phloem) are crucial for nutrient and water transportation in plants
• Capillary action enables water flow through narrow spaces in xylem and phloem
• Classes of Nutrients for Animals

  • Water
  • Carbohydrates
  • Proteins
  • Lipids (Fats)
  • Vitamins
  • Minerals
  • Nucleic Acids (conditionally essential)
• Essential Nutrients


  Cannot be synthesized by the animal's body in sufficient amounts and must be obtained from the diet
• Non-Essential Nutrients


  Can be synthesized by the animal's body from other precursors, but dietary intake can still be beneficial
• Macronutrients


  Needed in larger quantities by the body for energy production and building structures
• Micronutrients


  Required in smaller amounts but are vital for various biochemical reactions and maintaining health
• Mechanisms of Nutrient Procurement for Animals

  • Filter feeding
  • Tentacles
  • Suction
  • Beaks
  • Jaws and Teeth
• Homeostasis


  The ability of living organisms to maintain a stable internal environment despite changes in the external environment
• Key Variables in Homeostasis

  • Volume
  • Chemical substances
  • Temperature
• Homeostasis vs. Set Point

  Homeostasis doesn't necessarily mean a constant value, it refers to a relatively constant range around a set point
• Parts of the Homeostatic Control System

  • Sensors or Receptors
  • Control Center
  • Effectors
• Communication Pathways in Homeostasis

  • Afferent Pathway: Information flows from the receptors to the control center
  • Efferent Pathway: Information flows from the control center to the effectors
• Negative Feedback Mechanisms


  When a variable deviates from the set point, a response is triggered to bring it back
• Positive Feedback Mechanisms


  Create a snowball effect, amplifying the change rather than stopping it
• Alternation of Generations


  Common in plants, algae, and fungi. Involves both haploid and diploid cells in every generation, unlike sexual reproduction in animals
• Alternation of Generations in plants

  • In Bryophytes, the dominant generation is haploid and the gametophyte comprises the main plant
  • In tracheophytes, the dominant generation is diploid and the sporophyte comprises the main plant
• Dominant generation


  Grows larger and lives longer. Seen in the form of ferns, trees or other plants