Edexcel International GCSE Biology Study Notes

Edexcel International GCSE (9-1) Biology Student Book Notes

General Information

  • Authors: Philip Bradfield and Steve Potter

  • Publisher: Pearson Education Limited, 2019

  • Access to Resources: Each book comes with online access to ActiveBook for three years. Activation of the code can be done through the Pearson ActiveLearn website.

Course Structure

Contents Overview

  • UNIT 1: ORGANISMS AND LIFE PROCESSES
      - 1. LIFE PROCESSES
      - 2. THE VARIETY OF LIVING ORGANISMS

  • UNIT 2: ANIMAL PHYSIOLOGY
      - 3. BREATHING AND GAS EXCHANGE
      - 4. FOOD AND DIGESTION
      - 5. BLOOD AND CIRCULATION
      - 6. COORDINATION
      - 7. CHEMICAL COORDINATION
      - 8. HOMEOSTASIS AND EXCRETION
      - 9. REPRODUCTION IN HUMANS

  • UNIT 3: PLANT PHYSIOLOGY

  • UNIT 4: ECOLOGY AND THE ENVIRONMENT

  • UNIT 5: VARIATION AND SELECTION

  • UNIT 6: MICROORGANISMS AND GENETIC MODIFICATION

  • APPENDICES
      - A. A GUIDE TO EXAM QUESTIONS ON EXPERIMENTAL SKILLS
      - B. COMMAND WORDS

  • GLOSSARY

  • INDEX

About This Book

  • Target Audience: Students following the Edexcel International GCSE Biology and Science Double Award specifications.

  • Structure: Learning Objectives are indicated for each lesson; content is adapted for EAL (English as an Additional Language) students.

  • Assessment Overview: Details biological processes and concepts important in both written and practical assessments.

Assessment Overview

Examination Papers

  • Paper 1:
      - Specification Code: 4BI1/1B and 4SD0/1B
      - Externally assessed, covering 61.1% of the marks, lasting 2 hours.
      - Available in January and June. First assessment in June 2019.

  • Paper 2:
      - Code: 4BI1/2B
      - Externally assessed, covering 38.9% of the marks, lasting 1 hour 15 minutes.
      - Available in January and June. First assessment in June 2019.

Assessment Objectives and Weightings

  • AO1: Knowledge and understanding of biology (38%-42%)

  • AO2: Application of knowledge and understanding, analysis, and evaluation (38%-42%)

  • AO3: Experimental skills (19%-21%)

UNIT 1: ORGANISMS AND LIFE PROCESSES

1. LIFE PROCESSES

  • Living organisms composed of cells.

  • Eight life processes include:
      - Require nutrition (plants: autotrophic, animals: heterotrophic)
      - Respiration (energy release)
      - Excretion (removal of waste)
      - Response to stimuli (sensitivity)
      - Movement (muscles in animals, growth movements in plants)
      - Control internal conditions (homeostasis)
      - Reproduce (sexual and asexual)
      - Grow and develop (increase in size and complexity).

1.1 CELL STRUCTURE

  • Overview of typical plant and animal cells, focusing on organelles such as:
      - Nucleus: Control center, houses chromosomes (46 in humans).
      - Cytoplasm: Contains organelles, gel-like substance.
      - Cell Membrane: Semi-permeable barrier.
      - Mitochondria: Powerhouse of the cell; site of aerobic respiration.

Distinctive Features of Plant and Animal Cells:

  • Plant cells possess a cell wall (cellulose), chloroplasts (photosynthesis), and a permanent vacuole.

  • Animal cells contain small, temporary vacuoles.

FUNCTIONS OF ENZYMES

  • Enzymes are biological catalysts that speed up reactions without being consumed.

  • Each enzyme has a specific substrate and operates on the lock-and-key model.

  • Factors affecting enzyme activity:
      - Temperature (optimal around 37°C).
      - pH levels (neutral is optimal for most enzymes).

Enzymatic Reactions Example:

  • Amylase digestion of starch (starch → maltose).

1.2 DIFFUSION AND OSMOSIS

  • Diffusion: Movement from high to low concentration.

  • Influencing factors include concentration gradient, temperature, and surface area.

Osmosis:

  • Movement of water across a semi-permeable membrane from high to low concentration of water.

Experiment Example:

  • Investigating diffusion in agar jelly.

UNIT 2: ANIMAL PHYSIOLOGY

3. BREATHING AND GAS EXCHANGE
Structure of the Gas Exchange System

  • Components include:
      - Thorax, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli.

  • Alveoli adaptations include: large surface area, thin walls, moist lining for efficient gas exchange.

Mechanics of Ventilation

  • Inhalation and exhalation changes thoracic volume and pressure, facilitating airflow.

4. FOOD AND DIGESTION
Digestive System Components:

  • Includes mouth, oesophagus, stomach, small intestine, large intestine, pancreas.

Digestive Enzymes:

  • Breakdown of starch (amilase), proteins (proteases), and lipids (lipases).

Nutritional Needs:

  • Balanced diet must contain carbohydrates, lipids, proteins, vitamins, minerals, and water.

Practical Tests for Nutrients:

  • Starch: Iodine test (blue-black color indicates presence).

  • Glucose: Benedict's test (color change to precipitate).

  • Proteins: Biuret test (purple color indicates presence).

  • Lipids: Emulsion test (cloudy layer indicates fat).

Energy Content in Food

  • Different macronutrients provide various energy outputs:
      - Carbohydrates: 17extkJ/g17 ext{kJ/g}
      - Lipids: 39extkJ/g39 ext{kJ/g}
      - Proteins: 18extkJ/g18 ext{kJ/g}

Conclusion

  • Each dietary component has specific roles critical to maintaining health and supporting bodily functions. Research into nutritional science can inform dietary recommendations.