BGCSE Biology- Double Award Exam Notes

UNIT 1: LIVING THINGS

  • Cells: Building blocks of life, form plant and animal bodies.
  • Plant Cells: Cell wall, chloroplasts, and large vacuoles.
  • Animal Cells: No cell wall or chloroplasts.
  • Cell Membrane: Controls substance movement.
  • Cytoplasm: Site of chemical reactions.
  • Nucleus: Controls cell activities.
  • Mitochondrion: Energy production.
  • Ribosomes: Protein synthesis.
  • Cell Specialization: Cells develop unique features for specific functions.
  • Tissues: Groups of similar cells.
  • Organs: Structures of different tissues.
  • Systems: Groups of organs.
  • Diffusion: Movement from high to low concentration.
  • Osmosis: Diffusion of water.

UNIT 2: OBTAINING ESSENTIALS OF LIFE

  • Autotrophic Nutrition: Organisms make own food (e.g., photosynthesis).
  • Heterotrophic Nutrition: Organisms consume other organisms for food.
  • Balanced Diet: Includes carbohydrates, fats, proteins, vitamins, minerals.
  • Enzymes: Biological catalysts.
  • Digestion: Physical (chewing, peristalsis) and chemical (enzymes).
  • Respiration releases energy:
    • Aerobic: With oxygen, produces CO<em>2CO<em>2, H</em>2OH</em>2O, and energy.
    • Anaerobic: Without oxygen, produces lactic acid (animals) or ethanol and CO2CO_2 (plants).
  • Transport: Xylem (water, minerals) and phloem (food).
  • Circulation consists of:
    • Pulmonary (heart-lungs)
    • Systemic (heart-body).

UNIT 3: CONTROL OF THE INTERNAL ENVIRONMENT

  • Homeostasis: Maintaining constant internal conditions.
  • Excretion: Removal of toxic waste.

UNIT 4: RESPONSE AND COORDINATION

  • Nervous System: Sensory cells, neurons, and effectors.
  • Hormonal Coordination: Glands release hormones.
  • Drugs: Substances modifying body chemistry.
  • Drug Abuse: Dangers include dependence and tissue damage.

UNIT 5: REPRODUCTION

  • Asexual Reproduction: One parent, identical offspring.
  • Sexual Reproduction: Two parents, fusion of gametes.
  • Pollination: Transfer of pollen.
  • Fertilization: Fusion of nuclei.
  • Seed Dispersal: Seed spread.
  • Germination: Seed growth.

UNIT 6: LIVING THINGS AND THE ENVIRONMENT

  • Ecology: Study of organisms and environment.
  • Energy Flow: Sun -> Producers -> Consumers ->Decomposers.
  • Food Chains/Webs: Energy transfer pathways.
  • Human Activities: Deforestation, pollution.
  • Conservation: Protecting natural resources.

UNIT 7: BIOTECHNOLOGY

  • Biotechnology: Application of biological systems to industries.
  • Examples: Bread, medicines, fermentation.