IGCSE Biology Overview Lecture Notes

Introduction

• Focus on covering all major spec points for IGCSE Biology.
• Importance of revision guides and perfect answers.
• Features of living organisms: Movement, Respiration, Sensitivity, Nutrition, Excretion, Reproduction, Growth.

Cells and Organelles

• Shared between Animal and Plant Cells:
  • Cell membranes, Cytoplasm, Nuclei, Ribosomes, Mitochondria.
• Unique to Plant Cells:
  • Cell wall, Vacuole, Chloroplasts.

Functions of Organelles

• Nucleus: Controls cell activities.
• Cytoplasm: Site of chemical reactions.
• Cell Membrane: Regulates entry and exit of substances.
• Ribosomes: Site of protein synthesis.
• Cell Wall (plants): Made of cellulose, provides support and protection.
• Vacuole: Contains cell sap, maintains cell structure.
• Chloroplasts: Contain chlorophyll for photosynthesis.

Types of Cells

• Eukaryotes vs. Prokaryotes:
  • Eukaryotes: Membrane-bound organelles, e.g., animal cells.
  • Prokaryotes: No membrane-bound organelles, e.g., bacteria.

Specific Cells

• Bacterial Cells:
  • Cell Wall, Slime Capsule, Flagella, Circular Chromosome, Plasmids.
  • Pathogenic and Non-Pathogenic examples.
• Viruses:
  • Protein coat, DNA/RNA, Non-living, Always pathogenic.
• Protists:
  • Dustbin Kingdom, diverse properties.
  • Examples: Plasmodium (malaria-causing).
• Fungi:
  • Plant-like structure, no chloroplasts.
  • Hyphae, Mycelium, Saprotrophic nutrition.

Biological Organization

• Definitions:
  • Cells, Tissues, Organs, Organ Systems, Organisms.
• Organ Systems:
  • Examples: Digestive, Endocrine, Reproductive, Circulatory.

Enzymes and Digestion

• Enzyme Function:
  • Biological catalysts, not used up in reactions.
• Digestive Enzymes:
  • Amylase, Protease, Lipase.
• Factors Affecting Enzyme Activity:
  • Temperature, pH.

Transport Mechanisms

• Diffusion, Osmosis, Active Transport.
• Transport in Plants:
  • Xylem (water, minerals) and Phloem (sugars).

Photosynthesis

• Equation and Limiting Factors:
  • Light, CO2, Temperature.
• Leaf Structure and Function:

Human Nutrition and Diet

• Key Nutrients:
  • Carbohydrates, Proteins, Fats, Vitamins, Minerals, Water, Fiber.
• Factors Affecting Dietary Needs:
  • Age, activity level, health status.

Respiration

• Aerobic and Anaerobic Respiration:
  • Equations, ATP production.

Circulatory and Respiratory Systems

• Heart Structure and Function:
  • Blood flow through the heart.
• Blood Components:
  • Red and white blood cells, Plasma, Platelets.

Pathogen Defense and Immune System

• White Blood Cell Functions:
  • Phagocytes and Lymphocytes.

Excretion

• Processes in Humans and Plants:

Coordination and Response

• Nervous and Hormonal Systems:
  • Differences between systems.

Reproduction

• Sexual vs. Asexual Reproduction:
  • Characteristics and examples.

Genetics

• Mitosis and Meiosis:
  • Differences and purposes.
• Genetic Definitions:
  • Genes, Alleles, Genotype, Phenotype.

Ecology

• Definitions and Ecosystem Sampling:
  • Environment, Habitat, Population, Community.
• Food Chains and Pyramids of Biomass.

Human Impact on Environment

• Eutrophication, Greenhouse Effect, Acid Rain.

Use of Biological Resources

• Selective Breeding, Genetic Engineering:
  • Techniques and examples.

Conclusion

• Importance of understanding these concepts for exams.
• Encouragement to use revision guides and resources.