OxfordAQA International GCSE Biology: Circulation in humans: heart, vessels, blood and transplants (9201) – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover section 3.2.3, Circulation in humans (statements a to t), of the OxfordAQA International GCSE Biology (9201) specification, Version 5.2, for exams from May/June 2018 onwards. Learn the content from the study guide first. Course pages: hub and printable checklist.

Questions

1. Four blood vessels are described. Name each one. (a) Carries blood from the left ventricle to the body. [1] (b) Returns blood from the body to the right atrium. [1] (c) Carries blood from the right ventricle to the lungs. [1] (d) Brings blood from the lungs to the left atrium. [1]

2. Humans have a double circulatory system. Explain what this means and give one benefit. [3]

3. A student counts 75 pulse beats in 50 seconds. The left ventricle pushes out 58 cm³ of blood with each beat. (a) Calculate the heart rate in beats per minute. [2] (b) Calculate the volume of blood pumped in one minute, in dm³ to 2 significant figures. [2]

4. A man has coronary heart disease. (a) Explain how the disease reduces the supply of oxygen to his heart muscle. [2] (b) One coronary artery has an internal diameter of 4.0 mm. Fatty material narrows it to 1.6 mm. Calculate the percentage decrease in diameter. [2] (c) State how a stent helps. [1]

5. A patient has a faulty heart valve. (a) Describe the two main ways in which a heart valve can become faulty. [2] (b) The table gives data about two types of replacement valve, supplied for patients followed for 12 years.

	Biological valve	Mechanical valve
Patients needing a second valve operation (%)	38	9
Bleeding problems per 100 patients per year	0.9	2.4

A healthy 30-year-old needs a replacement valve. Evaluate the use of each type for this patient and reach a conclusion. [4]

6. (a) State where the natural pacemaker is found and what it controls. [2] (b) State what an artificial pacemaker does. [1] (c) Give one reason why an artificial heart might be fitted to a patient. [1]

7. Three blood vessels have these features: vessel X: thick wall containing muscle and elastic fibres; vessel Y: wall one cell thick, very narrow; vessel Z: thin wall with valves. (a) Name vessels X, Y and Z. [3] (b) Explain why vessel Z has valves. [1] (c) Name one substance that passes from the blood into cells through the wall of vessel Y, and one that passes from cells into the blood. [1]

8. A microscope image shows a white blood cell (cell A) and a red blood cell (cell B). The image of cell A is 63 mm wide and its real width is 10.5 µm. Cell B is 45 mm wide in the same image. (a) Calculate the magnification of the image. [3] (b) Calculate the real width of cell B in µm. [2] (c) Cell B has no nucleus. Name the cell type and the pigment that fills it. [1]

9. Blood clots when a blood vessel is cut. (a) Describe how a clot forms. [3] (b) A sample of blood from a healthy person clots in 5.5 minutes. A sample from a patient taking a clot-preventing drug clots in 11.0 minutes. Calculate the percentage increase in clotting time. [2] (c) Suggest why a patient with a mechanical heart valve may be given such a drug. [1]

10. A hospital blood bank has 200 donors: 88 group O, 70 group A, 30 group B and 12 group AB. (a) Explain why blood typing is needed before a transfusion. [1] (b) Group A plasma contains anti-B antibodies. Explain why a group A patient should not be given group B red cells. [2] (c) Explain why group O is called the universal donor. [1] (d) Calculate the percentage of these donors whose red cells could be given safely to a group A patient. [2] (e) State which recipient group can safely receive red cells from every donor group. [1]

11. A 45-year-old patient has heart failure. Of 250 patients on the waiting list for a heart transplant, 14 per cent die before a donor heart is found. (a) Calculate how many of the 250 patients die while waiting. [1] (b) Explain how antibodies cause a transplanted heart to be rejected. [2] (c) Describe two ways of reducing the chance of rejection. [2] (d) Evaluate the use of an artificial heart compared with waiting for a transplant. [3]

12. The table shows data for a woman at rest and during exercise.

	Heart rate (beats per minute)	Volume per beat (cm³)
At rest	72	70
Exercise	156	95

(a) Calculate the volume of blood pumped per minute at rest and during exercise. [2] (b) Calculate the percentage increase in volume pumped per minute during exercise. Give your answer to 3 significant figures. [2] (c) Explain why the volume of blood pumped per minute increases during exercise. [1]

Answers

1. (a) Aorta [1]. (b) Vena cava [1]. (c) Pulmonary artery [1]. (d) Pulmonary vein [1]. [4] Examiner insight: Answers such as “the artery” or “the vein” are too vague; give the full name.

2. There are two separate circuits [1]: one takes blood from the heart to the lungs and back, the other takes blood from the heart to all the other organs and back [1]. Benefit: after passing through the lungs the blood goes back to the heart for a second push, so it arrives at the organs at higher pressure [1]. [3] Examiner insight: Say that blood goes through the heart two times on each complete circuit; “two sides” alone is thin.

3. (a) Heart rate = 75 ÷ 50 × 60 [1] = 90 beats per minute [1]. (b) Volume = 58 × 90 = 5220 cm³ [1] = 5.22 dm³, so 5.2 dm³ per minute [1]. [4] Examiner insight: Show the conversion to one minute and the cm³ to dm³ step; visible steps are easier to credit.

4. (a) Fatty deposits on the inner wall of a coronary artery make its channel narrower [1]; less blood flows to the heart muscle, so it receives less oxygen [1]. (b) Decrease = 4.0 − 1.6 = 2.4 mm, and 2.4 ÷ 4.0 × 100 [1] = 60 per cent [1]. (c) A stent holds the artery open, so blood flows more freely [1]. [5] Examiner insight: Link the narrowing to a lack of oxygen for the muscle. In percentage change, divide by the original value.

5. (a) The valve tissue stiffens so it cannot open fully [1]; the valve develops a leak [1]. (b) Biological valve: fewer bleeding problems (0.9 against 2.4 per 100 patients per year) [1] but 38 per cent need a second operation, compared with 9 per cent for a mechanical valve [1]. Mechanical valve: far fewer repeat operations, which matters for a 30-year-old who will live with the valve for decades, but more bleeding problems, linked to anticoagulant drugs needed to stop clots forming on the valve [1]. Conclusion supported by the data, for example a mechanical valve because repeat surgery is much less likely, with bleeding risk monitored [1]. [6] Examiner insight: An evaluation gains credit when it uses figures for both options and then commits to a conclusion for this patient.

6. (a) Right atrium [1]; the resting heart rate [1]. (b) It is an electrical device that corrects irregularities in the heart rate [1]. (c) To keep the patient alive while waiting for a transplant, or to let the heart rest and recover [1]. [4] Examiner insight: Name the chamber, not just “the heart”, and state the function precisely.

7. (a) X is an artery [1]; Y is a capillary [1]; Z is a vein [1]. (b) Valves prevent back-flow of blood, so it moves only towards the heart [1]. (c) Oxygen or glucose passes into cells, and carbon dioxide passes into the blood [1]. [5] Examiner insight: In part (c) give one substance for each direction.

8. (a) Convert: 10.5 µm = 0.0105 mm [1]; magnification = 63 ÷ 0.0105 [1] = × 6000 [1]. (b) Real width = 45 ÷ 6000 = 0.0075 mm [1] = 7.5 µm [1]. (c) Red blood cell, containing haemoglobin [1]. [6] Examiner insight: Put both lengths into the same unit before dividing, and write the formula first.

9. (a) Platelets help the blood clot at the wound; a series of enzyme-controlled reactions takes place [1]; fibrinogen is changed to fibrin [1]; fibrin forms a network of fibres that traps blood cells to form the clot [1]. (b) Increase = 11.0 − 5.5 = 5.5 minutes; 5.5 ÷ 5.5 × 100 [1] = 100 per cent [1]. (c) Blood can clot on the artificial valve surface, and the drug reduces this risk [1]. [6] Examiner insight: Name both fibrinogen and fibrin and say which changes into which; platelets do not turn into fibrin.

10. (a) A patient given red cells carrying an antigen their antibodies recognise would have those cells attacked, so the groups must be matched [1]. (b) Group B red cells carry B antigens [1]; the group A patient’s anti-B antibodies would attack them [1]. (c) Group O red cells have no A or B antigens, so no recipient’s antibodies attack them [1]. (d) Compatible donors are group O and group A: 88 + 70 = 158 [1]; 158 ÷ 200 × 100 = 79 per cent [1]. (e) Group AB [1]. [7] Examiner insight: Say which group is donor and which is recipient, and link antigens to antibodies.

11. (a) 14 ÷ 100 × 250 = 35 patients [1]. (b) The donor heart has antigens that are different from the recipient’s own [1]; the recipient’s antibodies do not recognise them as part of the body and attack them [1]. (c) Use a donor with a tissue type similar to the recipient’s [1]; treat the recipient with drugs that suppress the immune system [1]. (d) Artificial heart: no wait for a donor, and no rejection [1]; but risks of blood clots, infection or mechanical or power failure, and it is mostly used as a temporary measure [1]. Transplant: a living organ does the whole job, but donors are scarce and drugs are needed to prevent rejection; a supported judgement, for example using an artificial heart to keep this patient alive while waiting for a transplant [1]. [8] Examiner insight: A balanced evaluation names an advantage and a disadvantage for both options, then uses the waiting-list figure in a judgement.

12. (a) Rest: 72 × 70 = 5040 cm³ per minute [1]. Exercise: 156 × 95 = 14 820 cm³ per minute [1]. (b) Increase = 14 820 − 5040 = 9780; 9780 ÷ 5040 × 100 [1] = 194 per cent (3 s.f.) [1]. (c) Muscles need more oxygen and glucose for more respiration, so more blood must be delivered [1]. [5] Examiner insight: Give the number of significant figures asked for, and tie the extra blood flow to oxygen and glucose supply.

Where marks are usually lost

• Naming vessels by oxygen content and calling the pulmonary vein deoxygenated.
• Using the new value rather than the starting value as the divisor in a percentage change.
• Forgetting to convert micrometres to millimetres, or minutes to seconds, before calculating.
• Describing a stent as removing the fatty material, rather than holding the artery open.
• Writing a one-sided evaluation with no judgement for the patient described.
• Saying “the body rejects it” without antibodies and antigens.
• Reversing donor and recipient when using the compatibility table.

Next steps

• Revise with the revision notes.
• Re-read the study guide.
• Return to the OxfordAQA IGCSE Biology hub and the printable checklist.
• Try all free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

OxfordAQA International GCSE Biology (9201), specification Version 5.2, for exams May/June 2018 onwards, published by OxfordAQA. These questions follow section 3.2.3, statements a to t.