Biology - Tara's IGCSE Study Hub

Topics 1–4 — Study Guides & Challenge Exams

Full guide, Challenge Prep and six Challenge papers for each topic.

Every Biology exam is Challenge level. Unlike Physics and Chemistry, there are no standard mocks here — each topic has 3 Paper 2 and 3 Paper 4 papers, all pitched harder than a real Cambridge paper. So there is no easy option to pick, and a score that looks low here would normally be higher on the real exam.

Topic 1: Characteristics and Classification of Living Organisms

MRS GREN, the binomial system, dichotomous keys, kingdoms, vertebrates and arthropods

4 subtopics · 1.1 – 1.4 · Guide + Challenge Prep + 6 Challenge exams

Topic 2: Organisation of the Organism

Animal, plant and bacterial cells, specialised cells, tissues and organs, magnification

3 subtopics · 2.1 – 2.3 · Guide + Challenge Prep + 6 Challenge exams

Topic 3: Movement Into and Out of Cells

Diffusion, osmosis and water potential, active transport, surface area to volume

4 subtopics · 3.1 – 3.4 · Guide + Challenge Prep + 6 Challenge exams

Topic 4: Biological Molecules

Carbohydrates, proteins and fats, the five food tests, and the structure of DNA

4 subtopics · 4.1 – 4.4 · Guide + Challenge Prep + 6 Challenge exams

Topic 5: Enzymes

How enzymes work, the active site, temperature and pH, and denaturation

1 subtopic · 5.1 · Guide + Challenge Prep + 6 Challenge exams

Topic 6: Plant Nutrition

Photosynthesis, limiting factors, and how a leaf is built for the job

2 subtopics · 6.1 – 6.2 · Guide + Challenge Prep + 6 Challenge exams

Topic 7: Human Nutrition

Diet, the digestive system, the three enzymes, and absorption

5 subtopics · 7.1 – 7.5 · Guide + Challenge Prep + 6 Challenge exams

Topic 8: Transport in Plants

Xylem and phloem, root hair cells, the transpiration stream, and how sugar moves from source to sink

4 subtopics · 8.1 – 8.4 · Guide + Challenge Prep + 6 Challenge exams

Topic 9: Transport in Animals

The double circulation, the mammalian heart, arteries, veins and capillaries, and what blood is made of

4 subtopics · 9.1 – 9.4 · Guide + Challenge Prep + 6 Challenge exams

Topic 10: Diseases and Immunity

Pathogens, the body’s defences, how vaccination works, and the cholera toxin

5 subtopics · 10.1 – 10.5 · Guide + Challenge Prep + 6 Challenge exams

Topic 11: Gas Exchange in Humans

Gas exchange surfaces, the breathing system, ventilation, and how exercise changes it

4 subtopics · 11.1 – 11.4 · Guide + Challenge Prep + 6 Challenge exams

Topic 12: Respiration

Uses of energy, aerobic and anaerobic respiration, lactic acid and the oxygen debt

3 subtopics · 12.1 – 12.3 · Guide + Challenge Prep + 6 Challenge exams

Topic 13: Excretion in Humans

The kidneys and the nephron, the liver and deamination, and why urea must go

4 subtopics · 13.1 – 13.4 · Guide + Challenge Prep + 6 Challenge exams

Topic 14: Coordination and Response

Neurones and reflexes, the eye, hormones, homeostasis and tropisms — the biggest topic on the syllabus

5 subtopics · 14.1 – 14.5 · Guide + Challenge Prep + 6 Challenge exams

Topic 15: Drugs

What a drug is, antibiotics, and how resistance develops

3 subtopics · 15.1 – 15.3 · Guide + Challenge Prep + 6 Challenge exams

Topic 16: Reproduction

Asexual and sexual reproduction, flowers, human reproduction, hormones and STIs

6 subtopics · 16.1 – 16.6 · Guide + Challenge Prep + 6 Challenge exams

Topic 17: Inheritance

Genes and proteins, mitosis and meiosis, monohybrid crosses, codominance and sex linkage

5 subtopics · 17.1 – 17.5 · Guide + Challenge Prep + 6 Challenge exams

Topic 18: Variation and Selection

Variation and mutation, adaptive features, natural selection and selective breeding

4 subtopics · 18.1 – 18.4 · Guide + Challenge Prep + 6 Challenge exams

Topic 19: Organisms and their Environment

Energy flow, food webs, pyramids, nutrient cycles and populations

5 subtopics · 19.1 – 19.5 · Guide + Challenge Prep + 6 Challenge exams

Topic 20: Human Influences on Ecosystems

Food supply, habitat destruction, pollution and eutrophication, and conservation

4 subtopics · 20.1 – 20.4 · Guide + Challenge Prep + 6 Challenge exams

Topic 21: Biotechnology and Genetic Modification

Bacteria and yeast in industry, enzymes, fermenters, and genetic modification

3 subtopics · 21.1 – 21.3 · Guide + Challenge Prep + 6 Challenge exams

Challenge Exams

📝 Biology Challenge Exams

Paper 2 (MCQ, 40 marks, 45 min) + Paper 4 (Theory, 80 marks, 1 h 15 min)

24 papers across Topics 1–4 · all Challenge level

Resources

Complete Study Guide — Part 1

Reference for Topics 1–10 (legacy, pre-dates the topic guides)

Complete Study Guide — Part 2

Reference for Topics 11–15 (legacy, pre-dates the topic guides)

Feynman Lab: Chemical Digestion

Explain-it-simply walkthrough of syllabus 7.4

🎬 Lesson library — animated lessons, all 15 topics

The original animated lesson set — still the fastest way to cover Topics 5–15.

1. Characteristics & Classification

3. Movement In & Out of Cells

4. Biological Molecules

6. Plant Nutrition

7. Human Nutrition

8. Transport in Plants

9. Transport in Animals

10. Diseases & Immunity

11. Respiration & Gas Exchange

12. Coordination & Response

13. Excretion & Homeostasis

14. Plant Reproduction

15. Human Reproduction