CIE IGCSE Biology Lecture Notes

Introduction

• Focus on CIE IGCSE Biology
• Perfect answer guides available online
• Lecture covers features of living organisms, classification, dichotomous keys, plant and animal cells, and more

Characteristics of Living Organisms

• Common features: Movement, Respiration, Sensitivity, Nutrition, Excretion, Reproduction, Growth (MRS GREN)
• Non-living things (e.g., viruses) do not exhibit these features

Classification

• Binomial naming system: Genus and species, e.g., Myobacterium tuberculosis
• Definition of species: Groups of organisms that can produce fertile offspring
• Traditional classification: Based on evolutionary similarities, morphology, and anatomy
• Modern classification: Based on DNA base sequences and protein structures

Dichotomous Keys

• Method to identify organisms using a series of choices based on their features
• Example given with five insects

Kingdoms

• Five kingdoms: Plants, animals, protists, bacteria, fungi
• Vertebrates: Animals with backbones (e.g., mammals, birds, reptiles, fish, amphibians)
• Invertebrates: Animals without backbones (e.g., arthropods)

Plant Cells

• Flowering plants (angiosperms): Produce flowers, fruits, seeds, have root systems, transport systems
• Ferns and viruses: Ferns have simple roots and reproduce via spores; viruses consist of genetic material surrounded by a protein coat

Cell Types

• Bacterial cells: Have cell walls, circular chromosomes (nucleoid), sometimes have flagella
• Viruses: Non-living, always pathogenic, contain DNA or RNA
• Protists: Diverse group, some with plant-like or animal-like features
• Fungi: Have cell walls made of chitin, perform saprotrophic nutrition
• Animal and plant cells: Share cell membranes, cytoplasm, nuclei; plant cells also have cell walls, vacuoles, and chloroplasts

Differentiation and Organization

• Levels of organization: Cells, tissues, organs, organ systems, organisms
• Importance of specialized cells (e.g., red blood cells, muscle cells, nerve cells)

Transport in Plants

• Xylem: Transports water up the plant
• Phloem: Transports sugars up and down the plant
• Transpiration: Loss of water vapor from leaves, important for nutrient transport
• Factors affecting transpiration: Light, humidity, temperature, wind

Human Biology

• Importance of a balanced diet
• Digestive enzymes: Amylase, protease, lipase
• Digestive system: Mouth, esophagus, stomach, small intestine, large intestine
• Heart and circulation: Double circulatory system, heart structure and function
• Blood vessels: Arteries, veins, capillaries
• Components of blood: Red blood cells, white blood cells, plasma, platelets

Respiration and Energy

• Aerobic respiration: Glucose + oxygen → carbon dioxide + water + energy
• Anaerobic respiration: Occurs in absence of oxygen, less efficient
• Differences between plant and animal respiration

Homeostasis

• Regulation of internal conditions (e.g., temperature, blood sugar)
• Role of skin in thermoregulation

Reproduction

• Sexual vs. asexual reproduction
• Plant reproduction: Pollination, fertilization, seed formation
• Human reproduction: Male and female reproductive systems
• Importance of hormones (e.g., insulin, sex hormones)

Genetics

• DNA structure and function
• Genetic engineering: Uses and techniques
• Inheritance and Punnett squares
• Sex linkage and codominance

Ecology

• Ecosystems, food chains, and food webs
• Human impact: Deforestation, pollution, conservation efforts
• Nitrogen and carbon cycles

Exam Tips

• Understanding key concepts and definitions
• Knowing how to apply them in exam questions
• Importance of using correct scientific terminology

These notes provide a concise yet comprehensive overview of the topics covered in the lecture. They highlight the essential concepts and provide a framework for studying and revision.