Practise 32 real questions on Transport in humans: heart and blood from 2021 to 2026. See the answer and explanation as soon as you answer.
Transport in humans: heart and blood is one of the 13 main topics in our O Level Biology (Cambridge (CAIE) 5090) question bank, and about 5% of its real questions come from it. Tayyari Karo has 32 real questions on this topic from 2021 to 2026, from Paper 1, Paper 2, Paper 4; 26 are multiple choice and marked instantly, and the rest are structured questions with a model answer. By difficulty: 24 medium, 5 hard, 3 easy.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
These are real past-paper questions. Think of your answer first, then open the explanation.
The mean blood pressure is measured in the pulmonary artery, pulmonary vein, aorta and vena cava of a human. Which blood vessel is most likely to be the pulmonary artery? (Pressures in mm Hg: A 3, B 9, C 12, D 120.)
Answer: C. C (12 mm Hg)
The pulmonary artery has lower pressure than the aorta (D) but higher than the veins (A and B).
What happens during blood clotting?
Answer: D. Soluble fibrinogen is converted to insoluble fibrin.
A person's cuts do not heal and blood does not clot easily. What may cause this?
Answer: C. lower than normal platelets
Platelets are needed for clotting.
Blood pressure was measured in the pulmonary artery, pulmonary capillaries and pulmonary vein.
Which results could be correct? (blood pressure / kPa)
Answer: A. artery 14, capillaries 8, vein 5
Pressure is highest in the artery leaving the heart, lowest in the vein returning.
Which blood vessels carry deoxygenated blood?
Answer: B. pulmonary artery and hepatic vein
Some people have a rare heart condition in which the lower left chamber has not developed properly and is much smaller than normal. The immediate result is lower than normal blood flow into which blood vessel?
Answer: A. aorta
6 (a)(i) Name the chamber of the heart with the thickest wall. [1]
(ii) State what causes the sound of the heartbeat. [1]
(iii) Name the blood vessel carrying blood from the aorta to the liver. [1]
(iv) State one function of blood plasma. [1]
(b) Explain the difference between antibodies and antibiotics. [3]
(c) Describe how natural selection has led to antibiotic-resistant bacteria. [5]
(a)(i) Left ventricle. (a)(ii) Closing of the heart valves. (a)(iii) Hepatic artery. (a)(iv) Plasma transports substances e.g. clotting factors/dissolved nutrients.
(b) Antibodies are produced by white blood cells in response to an antigen and are specific; antibiotics are drugs administered to kill bacteria. [any 3]
(c) Mutation gives variation; antibiotics kill susceptible bacteria leaving resistant survivors; survivors reproduce and pass resistance alleles over generations; misuse increases the resistant proportion. [any 5]
Selection: resistant bacteria survive antibiotic treatment and reproduce.
(a) Match each blood component to its function: red blood cell / platelet / plasma / phagocyte / lymphocyte to engulfs pathogens / transports oxygen / makes antibodies / transports fibrinogen / involved in clotting. [3] (b)(i) Explain how a red blood cell is specialised for transporting oxygen. [3] (b)(ii) Suggest two factors that could change the red blood cell count in a 25-year-old female. [2]
(a) Red blood cell - transports oxygen; platelet - involved in clotting; plasma - transports fibrinogen; phagocyte - engulfs pathogens; lymphocyte - makes antibodies. (b)(i) No nucleus (more room for haemoglobin), biconcave shape (large surface area), contains haemoglobin (binds oxygen). (b)(ii) Living at high altitude (more RBCs); smoking; pregnancy (lower); blood loss/anaemia; exercise training.
Model answers; verify with 5090_w23_ms_21.
| Session | Paper 1 | Paper 2 | Paper 4 |
|---|---|---|---|
| May/June 2026 | 3 | – | – |
| May/June 2025 | 4 | – | – |
| Oct/Nov 2025 | 2 | 1 | – |
| May/June 2024 | 2 | 1 | 1 |
| Oct/Nov 2024 | 2 | – | – |
| May/June 2023 | 2 | 1 | – |
| Oct/Nov 2023 | 1 | 1 | – |
| May/June 2022 | 3 | – | – |
| Oct/Nov 2022 | 1 | 1 | – |
| May/June 2021 | 3 | – | – |
| Oct/Nov 2021 | 3 | – | – |
32 real O Level Biology (5090) questions on Transport in humans: heart and blood from 2021 to 2026, from Paper 1, Paper 2, Paper 4. Each one shows the year, session and paper it came from.
Yes. Every question shows the correct answer and a short explanation the moment you answer.
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