‹ Biology simulationsBiology · IGCSE 0610 · 11 Gas exchange in humans and Respiration (11 and 12)Eight 3D simulations covering Topic 11 Gas exchange in humans and Topic 12 Respiration. Explore the breathing system, breathe in and out, test inspired and expired air, compare aerobic and anaerobic respiration and pay back an oxygen debt. Tabs marked Extended cover the Supplement.
Air travels through the larynx, trachea, bronchi and bronchioles to millions of tiny air sacs, the alveoli, where gas exchange happens. The lungs sit inside the ribcage above the diaphragm. Click each part; the Extended view shows how the airways are kept clean.
Muscles change the volume of the thorax, which changes the pressure inside it, and air moves from high pressure to low pressure. Breathe in and out and watch the ribs, intercostal muscles and diaphragm.
Oxygen diffuses from the air in the alveoli into the blood in the capillaries, and carbon dioxide diffuses the other way. Gas exchange surfaces have four features that make this fast. Switch each one off to see why it matters.
Breathe in through one tube of limewater and out through another, using the valves of the apparatus. Limewater turns milky with carbon dioxide. Then compare the full composition of the air we breathe in and out.
Measure the rate (breaths per minute) and depth (volume of each breath) of breathing at rest and during exercise. The trace shows the volume of air in the lungs over time.
Respiration is the chemical reactions in cells that break down nutrient molecules to release energy. With oxygen it is aerobic; without oxygen, anaerobic, which releases much less energy. Compare the three types, and see what the energy is used for.
Yeast respires sugar anaerobically and gives off carbon dioxide. Put flasks of yeast and sugar solution into water baths at different temperatures and measure the carbon dioxide released in 10 minutes from the size of the balloon.
| temperature / °C | CO₂ in 10 min / cm³ |
|---|
During vigorous exercise muscles cannot get enough oxygen, so they also respire anaerobically and lactic acid builds up. After exercise, extra oxygen is needed to remove it: the oxygen debt. Sprint, then stop, and watch how it is paid back.
Eight interactive 3D simulations for Cambridge IGCSE Biology 0610 topics 11 Gas exchange in humans and 12 Respiration: a clickable breathing system with the trachea lining, ventilation by the ribs, intercostal muscles and diaphragm, the features of alveoli, limewater and the composition of inspired and expired air, exercise and breathing, aerobic and anaerobic respiration with equations, yeast respiration at different temperatures, and the oxygen debt.
Eight 3D simulations covering Topic 11 Gas exchange in humans and Topic 12 Respiration. Explore the breathing system, breathe in and out, test inspired and expired air, compare aerobic and anaerobic respiration and pay back an oxygen debt. Tabs marked Extended cover the Supplement.
Gas exchange and respiration is a free, browser-based simulation for Cambridge IGCSE Biology 0610 (topic 11 Gas exchange in humans; topic 12 Respiration, sections 12.1 Respiration, 12.3 Anaerobic respiration). The course is assessed in Paper 1/2 (Multiple choice), Paper 3/4 (Theory), Paper 5 (Practical Test), Paper 6 (Alternative to Practical). Syllabus for examination in 2026-2028. There are 8 tabs, each a self-contained experiment with its own controls and live readings, and nothing to install: it runs on a laptop, tablet or classroom projector.
Full syllabus map: IGCSE Biology 0610 topic 11 and IGCSE Biology 0610 topic 12.
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