Gas exchange in humans — IGCSE Science - Combined (0653) questions by topic
Labelling the breathing system, reading breathing-rate graphs and explaining why breathing rate rises during exercise are the recurring demands here, alongside naming the diffusion process that moves oxygen into red blood cells at the alveolar surface. State, identify and describe lead the command words, each wanting a precise structure or process named rather than its general importance.
Only 8 real questions currently sit in this set, spanning 2023 to 2025 papers, worth 1 to 10 marks apiece, so every mark matters more than in larger topics. Submitting answers for instant marking is especially useful here for catching a mislabelled structure, such as confusing goblet cells with cilia, before it recurs across several questions.
What examiners look for
- A common mistake is confusing goblet cells with cilia, wrongly stating that goblet cells trap and move mucus rather than produce it.
- Rounding answers to a whole number is often overlooked when the question specifies it.
- Breathing rate increases should be explained in terms of rising carbon dioxide concentration in the blood, not simply the body needing more oxygen.
- Alveolar surface questions are marked down when candidates describe gas exchange itself, or its importance, instead of the physical features of the surface.
- Strong answers on the alveolar surface most often cite a moist surface as the valid feature, and correctly recognise cilia as the structures that move mucus.
May–June 2025, Paper 22
The graphs show how the rate and depth of breathing varies when a student does four different activities. Which graph shows when the student is most active? Each graph (A-D) plots…
Answer this question and get it marked →May–June 2025, Paper 43
Fig. 3.1 shows part of the breathing system in humans. It shows a branching airway leading to clusters of small rounded sacs. One of the small tubes leading to a cluster of sacs…
Answer this question and get it marked →May–June 2023, Paper 31
Fig. 4.1 shows a model of the human gas exchange system. Draw a label line and the letter D to identify the diaphragm on Fig. 4.1.
Answer this question and get it marked →May–June 2023, Paper 42
Fig. 7.1 shows the gas exchange surface in humans (capillary wall, wall of alveolus, red blood cells, direction of oxygen movement). State the name of the process by which oxygen…
Answer this question and get it marked →October–November 2023, Paper 32
Fig. 1.1 is a diagram of the human gas exchange system, with parts labelled A, B, C, D, E. State the letter in Fig. 1.1 that identifies: one of the bronchi; the trachea.
Answer this question and get it marked →October–November 2023, Paper 33
Fig. 1.1 is a diagram of the human gas exchange system, with parts labelled A, B, C, D, E. State the letter in Fig. 1.1 that identifies: one of the bronchi; the trachea.
Answer this question and get it marked →October–November 2023, Paper 41
Fig. 4.1 shows part of the breathing system in humans, with part X above a labelled rib. State the name of the part labelled X in Fig. 4.1.
Answer this question and get it marked →October–November 2023, Paper 43
Fig. 1.1 shows part of the breathing system in humans, with the trachea labelled and parts A and B also marked. State the names of the parts labelled A and B in Fig. 1.1. A = ...…
Answer this question and get it marked →Other IGCSE Science - Combined topics
- Practical skills (96)
- Motion, forces and energy (53)
- Electricity and magnetism (38)
- Waves (32)
- Human nutrition (23)
- Acids, bases and salts (22)
- Organisms and their environment (21)
- Organic chemistry (21)
- Reproduction (20)
- Thermal physics (20)
- Plant nutrition (19)
- The Periodic Table (18)