CIE IGCSE Biology Lecture Notes

Introduction

• Focus on CIE IGCSE Biology.
• Offers "perfect answers" for exams.
• Website resources: revision guides and courses available.

Core Biology Concepts

Features All Living Organisms Share (MRS GREN):

• Movement
• Respiration
• Sensitivity
• Growth
• Reproduction
• Excretion
• Nutrition
• Example: Viruses lack these features.

Classification of Organisms

• Binomial Naming System: Species and genus (e.g., Mycobacterium tuberculosis).
• Definition of Species: Groups that produce fertile offspring.
• Historical Classification: Based on morphology and anatomy.
• Modern Classification: DNA sequencing, amino acid and protein similarities.

Dichotomous Keys

• Used to identify organisms based on physical characteristics.
• Example walkthrough of insect identification.

Biological Taxonomy

Five Kingdoms

• Plants
• Animals
• Protists
• Bacteria
• Fungi

Vertebrates

• Mammals: Hair/fur, mammary glands.
• Birds: Feathers, scales on legs.
• Reptiles: Dry, scaly skin.
• Fish: Scales, gills, lateral line.
• Amphibians: Moist skin.

Invertebrates

• Arthropods: Insects, arachnids, myriapods, crustaceans.

Plant Biology

Plant Structure

• Flowering Plants (Angiosperms): Flowers, fruits, seeds, transport systems.
• Ferns: Fronds, sporangia, simple root systems.

Viruses

• Consist of a protein coat and genetic material (DNA or RNA).
• Non-living, always pathogenic (e.g., flu, HIV).

Cell Biology

Prokaryotic vs Eukaryotic Cells

• Prokaryotes: No membrane-bound organelles.
• Eukaryotes: Nucleus, mitochondria, etc.

Specialized Cells

• Red Blood Cells: Transport oxygen, lack nucleus.
• Muscle Cells: Contract and relax.
• Ciliated Cells: Move mucus in the respiratory system.
• Nerve Cells: Conduct electrical impulses.
• Sperm and Egg Cells: Involved in reproduction.

Biological Processes

Photosynthesis

• Occurs in chloroplasts.
• Converts carbon dioxide and water into glucose and oxygen.
• Equation: 6CO2 + 6H2O → C6H12O6 + 6O2
• Limiting Factors: CO2, light intensity, temperature.

Plant Structures

• Leaf Anatomy: Waxy cuticle, upper epidermis, palisade mesophyll, spongy mesophyll, stomata.

Human Nutrition

• Balanced Diet: Carbohydrates, proteins, fats, vitamins, minerals, water, fiber.
• Deficiency Diseases: Kwashiorkor, scurvy, rickets, anemia.

Digestion

• Process: Breakdown of large molecules into small, absorbable ones.
• Enzymes: Amylase, protease, lipase.
• Absorption: Occurs in small intestine (villi and microvilli).

Transport Systems

Plant Transport

• Xylem: Transports water and minerals.
• Phloem: Transports sugars.

Human Circulatory System

• Heart Function: Double circulatory system.
• Vessels: Arteries, veins, capillaries.

Human Biology

Excretion

• Kidneys: Filtration, reabsorption, osmoregulation.

Nervous System

• Components: Central and peripheral nervous systems.
• Reflex Actions: Involuntary, fast responses.

Hormonal System

• Adrenaline: "Fight or flight" hormone.
• Insulin: Lowers blood glucose levels.

Ecology and Environment

Ecosystems

• Components: Producers, consumers, decomposers.
• Food Chains and Webs: Energy transfer, trophic levels.

Human Impact

• Pollution: Eutrophication, plastic waste.
• Climate Change: Greenhouse gases, global warming.

Conservation

• Sustainable Development: Balancing human needs with environmental protection.

Genetic Engineering

• Applications: Insulin production, genetically modified crops.
• Process: Recombinant DNA technology.

Recap and Resources

• Encouragement to explore additional resources and guides for further study.