Cambridge International GCSE Biology Overview

Introduction

• Lecture covers key topics for Cambridge IGCSE Biology
• Suitable for separate/triple biology, coordinated or combined
• Focus on most important information

Cell Biology

• All life consists of cells
  • Microscopes:
    • Light microscopes: view cells and nucleus
    • Electron microscopes: view finer details, organelles
    • Resolving power and resolution
  • Calculating Cell Size:
    • Magnification = Image size / Object size
    • Rearrange to find actual cell size
  • Cell Types:
    • Eukaryotic: nucleus with DNA (plant, animal cells)
    • Prokaryotic: no nucleus, DNA in plasmid
  • Cell Structures:
    • Cell membrane: semi-permeable
    • Cell wall (plants, bacteria): made of cellulose
    • Cytoplasm: site for chemical reactions
    • Mitochondria: respiration
    • Ribosomes: protein synthesis
    • Chloroplasts (plants): photosynthesis
    • Vacuole (plants): sap storage

Transport in Cells

• Diffusion: movement from high to low concentration, passive
• Osmosis: diffusion of water across a membrane
  • Practical with potatoes and sugar solutions
• Active Transport: movement against concentration gradient using energy

Biological Organization

• Cells form tissues, tissues form organs, organs form systems
  • Digestive System:
    • Acid, bile, and enzymes in digestion
    • Teeth and physical digestion
  • Enzymes:
    • Biological catalysts with specific actions
    • Lock and key model
    • Factors affecting enzyme activity: temperature, pH
  • Practical on enzyme activity with starch and iodine

Human Nutrition

• Balanced diet includes carbohydrates, fats, proteins, vitamins, minerals
  • Vitamins: C, D, and their deficiency diseases
  • Minerals: calcium, iron
• Food tests for nutrients

Respiration

• Breathing vs. Cellular respiration
  • Respiratory System:
    • Air pathway: trachea, bronchi, bronchioles, alveoli
    • Oxygen transport and CO2 exhalation
  • Heart and Circulation:
    • Double circulatory system
    • Heart structure and blood flow
    • Blood vessels: arteries, veins, capillaries
    • Heart health: CHD, stents, statins

Plant Biology

• Plant organs: leaves, roots, stems
  • Transpiration: water movement, factors affecting rate
  • Photosynthesis:
    • Equation and factors affecting rate
    • Practical with pondweed and light intensity

Disease and Immunity

• Non-communicable Diseases:
  • Examples: cardiovascular disease, diabetes, cancer
• Communicable Diseases:
  • Pathogens: viruses, bacteria, fungi, protists
  • Body's defenses: skin, mucus, white blood cells
  • Vaccines and immunity

Genetics and Inheritance

• DNA and Genes:
  • Structure and replication
  • Human Genome Project
  • Genotype vs. Phenotype
• Inheritance:
  • Dominant and recessive alleles
  • Genetic diagrams and Punnett squares

Evolution and Ecology

• Evolution: natural selection, adaptation
• Biodiversity and Human Impact:
  • Deforestation, climate change, and conservation efforts
• Ecological Interactions:
  • Food chains and trophic levels
  • Abiotic and biotic factors

Practical Applications of Biology

• Biotechnology: Genetic engineering, GM crops
• Sustainability: Food security, sustainable fishing

Conclusion

• Emphasis on understanding core concepts and application in real-world scenarios
• Encouragement for further study and exam preparation