plumiHaemoglobin and oxygen transport: Edexcel International A Level Biology questions
Edexcel International A Level Biology past-paper questions on 1.2.4 Haemoglobin and oxygen transport, 2019–2025, with mark schemes and examiner’s reports where available.
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Q2(a)(i)
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All 32 questions on Haemoglobin and oxygen transport, as a list
- June 2025, AS Unit 1, Q2(a)(i) (1 mark): Which describes this dissociation curve? (1) A linear curve showing a positive correlation B linear curve showing a negative correlation C sigmoid curve showing
- June 2025, AS Unit 1, Q2(a)(ii) (1 mark): Which name is given to the effect of increasing carbon dioxide concentration on this dissociation curve? (1) A Benedict B Bohr C Fick D Stahl
- June 2025, AS Unit 1, Q2(b) (3 marks): Explain how the structure of haemoglobin is related to its function in transporting oxygen and carbon dioxide. (3)
- October 2024, AS Unit 1, Q2(a) (1 mark): Blood may contain 5.3 million red blood cells in 1 mm3 of blood. One red blood cell can contain 270 million haemoglobin molecules. Calculate the number of haemo
- October 2024, AS Unit 1, Q2(b) (1 mark): Which of the following statements about the structure of haemoglobin are correct? 1. It is a fibrous protein 2. It has quaternary structure 3. It contains a
- October 2024, AS Unit 1, Q2(c)(i) (3 marks): Describe the changes in these types of subunits present during each stage of development. (3)
- October 2024, AS Unit 1, Q2(c)(ii) (2 marks): The oxygen affinity of fetal haemoglobin is different from adult haemoglobin. Explain why this difference ensures the fetus obtains enough oxygen during develop
- June 2024, AS Unit 1, Q8(a) (3 marks): Describe the structure of a haemoglobin molecule. (3)
- June 2024, AS Unit 1, Q8(b) (6 marks): The table shows some information about red blood cells from four species of air- breathing mammals. The species are listed by decreasing size. Oxygen-carrying M
- June 2024, AS Unit 1, Q8(c)(i) (2 marks): The decrease in percentage saturation with oxygen of myoglobin from 6 kPa to 4 kPa is 3%. Calculate the difference between this decrease and the decrease for ha
- June 2024, AS Unit 1, Q8(c)(ii) (2 marks): Describe the effect of the partial pressure of oxygen on the percentage saturation with oxygen of myoglobin. Use values from the graph to support your answer. (
- June 2024, AS Unit 1, Q8(c)(iii) (2 marks): Suggest why the dissociation curve for myoglobin is to the left of the curve for haemoglobin. (2)
- June 2024, Unit 4, Q8(a) (4 marks): Animals, such as seals, that spend much of their time underwater have very large spleens. Spleens store oxygenated red blood cells which are released into the b
- January 2024, AS Unit 1, Q1 (5 marks): Red blood cells transport oxygen to the cells of the body. Read through the following description of how oxygen is transported from the lungs to respiring cells
- June 2023, AS Unit 1, Q6(c) (1 mark): Name one organic molecule that contains iron. (1)
- June 2023, Unit 5, Q2(b)(i) (3 marks): Carbon monoxide binds to the haem group of haemoglobin. Explain how carbon monoxide will affect the production of ATP. (3)
- January 2023, AS Unit 1, Q7(c)(iii) (6 marks): Discuss why the blood of yaks enables these animals to live at high altitudes. Use all the information in this question to support your answer. (6)
- October 2022, AS Unit 1, Q3(d) (3 marks): Deoxygenated blood is taken to the lungs and oxygenated blood is taken away from the lungs. Complete the graph to show the changes in partial pressure of oxygen
- January 2022, AS Unit 1, Q8(c)(i) (2 marks): A p50 value is the partial pressure of oxygen that results in 50% saturation of haemoglobin. Calculate the largest difference in the p50 values between a person
- January 2022, AS Unit 1, Q8(c)(ii) (2 marks): Identify two conclusions, other than the difference in p50 values, that can be made from this graph. (2) Conclusion 1 Conclusion 2
- January 2022, AS Unit 1, Q8(c)(iv) (3 marks): Sickle cell disease can result in death. Explain why the changes in the structure of haemoglobin and the shape of the red blood cells could result in death in a
- January 2021, AS Unit 1, Q4(a)(i) (1 mark): State the role of the structure labelled P. (1)
- January 2021, AS Unit 1, Q4(b)(i) (2 marks): Explain why the oxygen dissociation curve of adult haemoglobin is different from that of fetal haemoglobin. (2)
- January 2021, AS Unit 1, Q4(b)(ii) (2 marks): The structures of adult and fetal haemoglobin are different. The diagram shows the structure of adult and fetal haemoglobin. α chain β chain α chain γ chain β c
- January 2020, AS Unit 1, Q7(a)(i) (1 mark): State what is meant by the term partial pressure. (1)
- January 2020, AS Unit 1, Q7(a)(ii) (3 marks): Explain how the structure of haemoglobin causes the oxygen dissociation curve of haemoglobin to be this sigmoidal (S) shape. (3)
- January 2020, AS Unit 1, Q7(b)(i) (1 mark): Suggest why the partial pressure of oxygen in the air in the alveoli is lower than in the atmosphere. (1)
- January 2020, AS Unit 1, Q7(b)(ii) (3 marks): Explain why the partial pressure of oxygen decreases as the blood flows through the arteries and into the veins. (3)
- January 2020, AS Unit 1, Q7(b)(iii) (1 mark): Determine the percentage saturation of haemoglobin in the blood as it leaves the lungs of the person at high altitude. Use the point marked X on the graph and t
- January 2020, AS Unit 1, Q7(b)(iv) (4 marks): Explain why the percentage saturation of haemoglobin in a person at high altitude is much lower than in a person at sea level. (4)
- June 2019, AS Unit 1, Q7(d)(ii) (2 marks): The red blood cells of the giraffe are about one third the size of human red blood cells, so that they can pass through the very narrow capillaries. The small s
- January 2019, AS Unit 1, Q8(c) (6 marks): Graph 1 shows the oxygen dissociation curve of haemoglobin for a mouse and for an elephant. Graph 1 elephant 100 mouse 80 Percentage 60 saturation of haemoglobi
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