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CAIE A Level Biology 9700

Transport in mammals questions

Exam-style questions on Transport in mammals, ordered from foundation to challenge. Pick one, write your answer the way you would in the exam, and it comes back marked against the mark scheme, point by point.

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Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.

  1. Describe4 marksStandardDescribe how the thickness of the wall of the left ventricle compares with that of the right ventricle, and explain the reason for this difference.
  2. Compare4 marksStandardA marathon runner becomes dehydrated after prolonged sweating without fluid replacement. Compare the composition of the runner's blood and the formation of tissue fluid in this dehydrated state with that of a…
  3. Explain4 marksStandardDuring strenuous exercise, muscle cells produce large amounts of carbon dioxide (CO₂). Explain how this increased CO₂ concentration affects the oxygen dissociation curve of haemoglobin and why this is important for…
  4. Describe5 marksStandardDuring vigorous exercise, muscle cells produce large amounts of carbon dioxide. Describe the role of carbonic anhydrase in red blood cells in the transport of this carbon dioxide to the lungs.
  5. Describe4 marksStandardA patient is diagnosed with a leaking left atrioventricular (bicuspid) valve. This means that the valve does not close completely during ventricular systole. Describe the effects of this condition on the pressure…
  6. Explain5 marksStandardExplain how the changes in pressure in the left atrium, left ventricle, and aorta during one complete cardiac cycle cause the opening and closing of the atrioventricular and semilunar valves. In your answer, refer to…
  7. Explain5 marksStandardThe aorta is the largest artery in the body. Its wall contains a high proportion of elastic fibres. During the cardiac cycle, the aorta expands when the left ventricle contracts and recoils when the ventricle relaxes…
  8. Describe4 marksStandardThe table below shows the pressures (mmHg) in the left atrium, left ventricle and aorta at four stages of one cardiac cycle in a healthy adult. Stage Left atrium Left ventricle Aorta 1 8 2 80 2 6 80 80 3 5 120 120 4 4…
  9. Explain5 marksStandardThe heartbeat is coordinated by a sequence of electrical impulses passing through specialised cardiac muscle tissue. The sinoatrial node (SAN), atrioventricular node (AVN), and Purkyne tissue each play distinct roles…
  10. Explain5 marksStandardA student observes a capillary network in a living hamster's cheek pouch under a microscope. They note that the capillary walls are extremely thin (only one cell thick), the lumen is very narrow, and the blood flow is…
  11. Describe4 marksStandardThe table below shows pressure changes in the left side of the heart during one cardiac cycle. Time (s) Left atrial pressure (mmHg) Left ventricular pressure (mmHg) Aortic pressure (mmHg) 0.0 5 0 80 0.1 8 5 80 0.2 6…
  12. Describe5 marksStandardThe table below shows the percentage saturation of haemoglobin with oxygen at different partial pressures of oxygen (pO₂) under two conditions: low CO₂ (5 kPa) and high CO₂ (8 kPa). pO₂ (kPa) % saturation (low CO₂) %…
  13. Explain4 marksStandardA student examines stained sections of a typical artery and a typical vein. The artery wall is much thicker and contains more smooth muscle and elastic fibres than the vein wall. Explain how these structural…
  14. Compare5 marksStandardA marathon runner's leg muscle is actively contracting. Samples are taken from the blood in the femoral vein leaving the leg and from the tissue fluid surrounding the muscle cells. Compare the composition of these two…
  15. Explain4 marksStandardDuring strenuous exercise, muscle cells produce large amounts of carbon dioxide. Explain the role of carbonic anhydrase in the transport of this carbon dioxide from the muscle cells to the lungs.
  16. Describe5 marksStandardA mountaineer stays at an altitude of 5000 m for several weeks. At high altitude, the partial pressure of oxygen in the atmosphere is very low. Describe how the transport of oxygen and carbon dioxide by the blood is…
  17. Explain4 marksStandardIn a study of carbon dioxide transport, blood samples were analysed. The results are shown in the table below. Form of CO2 transport Arterial blood (cm³ CO₂ per 100 cm³ blood) Venous blood (cm³ CO₂ per 100 cm³ blood)…
  18. Compare5 marksStandardThe aorta is an elastic artery that stretches during systole and recoils during diastole. Compare the structure of an elastic artery, such as the aorta, with that of a muscular artery, explaining how the structural…
  19. Describe5 marksStandardCapillaries are the primary site of exchange between blood and body cells. Describe how the structure of capillaries is adapted for this exchange, and explain the formation and functions of tissue fluid.
  20. Describe4 marksStandardAn athlete is running a long-distance race. In the leg muscles, there is an increased demand for oxygen and glucose, and a need to remove carbon dioxide and lactic acid. Describe, using named examples of vessels, how…
  21. Describe4 marksStandardIn a healthy human heart, the wall of the left ventricle is significantly thicker than the wall of the right ventricle. During a single cardiac cycle, the pressure in the left ventricle and the aorta changes, causing…
  22. Describe5 marksStandardDuring exercise, respiring tissues produce large amounts of carbon dioxide. In a red blood cell, carbon dioxide is converted to carbonic acid by carbonic anhydrase. Describe the subsequent chloride shift that occurs in…
  23. Describe5 marksStandardIn a capillary bed within skeletal muscle, describe the differences in fluid movement at the arteriole end compared to the venule end. Include in your answer the role of pressure differences and the structure of…
  24. Explain5 marksStandardDuring a cardiac cycle, the pressures in the left atrium, left ventricle, and aorta change as shown in the following data (typical values): Event Left atrial pressure (mmHg) Left ventricular pressure (mmHg) Aortic…
  25. Explain5 marksStandardThe mammalian heart is adapted to pump blood to both the pulmonary and systemic circulations. Explain how the structure of the heart, including differences in wall thickness and the coordination of its chambers, allows…
  26. Compare4 marksStandardA patient's blood test results are shown in the table. One type of white blood cell has a count outside the normal range. White blood cell type Patient count (cells per mm³) Normal range (cells per mm³) Neutrophils 900…
  27. Explain4 marksStandardAn athlete is running a marathon. Explain how water in the blood and tissue fluid is important for the circulation of the athlete during exercise.
  28. Describe5 marksStandardThe table below shows the partial pressure of oxygen (PO₂) and the corresponding percentage saturation of haemoglobin at two locations in the human body. Location PO₂ / kPa Percentage saturation of haemoglobin Alveoli…
  29. Explain4 marksStandardDuring vigorous exercise, muscle cells produce large amounts of carbon dioxide. This carbon dioxide diffuses into the blood plasma and then enters red blood cells. Explain the role of the enzyme carbonic anhydrase in…
  30. Explain4 marksStandardThe table below shows the percentage saturation of haemoglobin with oxygen at different partial pressures of oxygen (pO₂) and at two different pH values, representing conditions in the lungs (pH 7.4) and in respiring…
  31. Explain5 marksStandardExplain the sequence of events by which the sinoatrial node (SAN) initiates and coordinates the heartbeat, including the roles of the atrioventricular node (AVN) and Purkyne tissue. In your answer, explain why the…
  32. Describe5 marksStandardA student measured the partial pressures of oxygen and carbon dioxide in the lung alveoli and in a respiring muscle. The results are shown in the table. Location pO2 / kPa Haemoglobin saturation / % pCO2 / kPa Lung…
  33. Explain5 marksStandardThe mammalian heart is adapted for double circulation. Explain how the structure of the heart, including the thickness of its walls and the coordination of its beat, ensures efficient blood flow through the pulmonary…
  34. Describe6 marksChallengeA medical researcher is investigating how carbon dioxide (CO₂) produced by respiring tissues is transported in the blood to the lungs for exhalation. She measures the CO₂ content in arterial and venous blood samples…
  35. Describe6 marksChallengeTable 1 shows the blood cell counts from a healthy individual and from a patient suspected of having a bacterial infection. Blood component Healthy individual (cells per mm³) Patient (cells per mm³) Red blood cells 5.4…
  36. Describe6 marksChallengeA patient is diagnosed with a leaking left atrioventricular valve (mitral valve regurgitation). Describe the effect of this condition on the pressure changes in the left atrium and left ventricle during the cardiac…
  37. Explain5 marksChallengeIn a capillary network, the arteriole end has a blood hydrostatic pressure of approximately 4.3 kPa and a plasma colloid osmotic (oncotic) pressure of approximately 3.6 kPa. At the venule end, the blood hydrostatic…
  38. Describe7 marksChallengeDescribe the internal structure of the mammalian heart, explaining the difference in thickness between the walls of the atria and ventricles and between the left and right ventricles. Also describe the pressure changes…
  39. Describe7 marksChallengeDuring a dissection of a mammalian heart, a student observes that the walls of the atria are much thinner than those of the ventricles, and the wall of the left ventricle is noticeably thicker than that of the right…
  40. Explain7 marksChallengeThe table shows the thickness of the chamber walls in a mammalian heart. Chamber Wall thickness (mm) Right atrium 2 Left atrium 3 Right ventricle 5 Left ventricle 15 Explain how these differences in wall thickness…
  41. Explain7 marksChallengeDuring vigorous exercise, the concentration of carbon dioxide in actively contracting muscle cells rises. Explain the mechanism by which this increased CO2 affects the transport of oxygen by haemoglobin, and state why…
  42. Describe5 marksChallengeIn an investigation of gas transport in a mammal, the partial pressures of oxygen (pO₂) and carbon dioxide (pCO₂) and the percentage saturation of haemoglobin were measured in blood leaving the lungs and in blood…
  43. Describe6 marksChallengeA person becomes dehydrated after prolonged exercise without drinking water. Describe the effects of dehydration on the composition of blood and the formation and composition of tissue fluid. In your answer, refer to…
  44. Compare7 marksChallengeThe aorta is an elastic artery carrying blood away from the left ventricle, while the brachial artery in the arm is a muscular artery carrying blood to the upper limb. Compare the structure of the aorta and the…
  45. Explain5 marksChallengeExplain how the sequence of electrical activity from the sinoatrial node (SAN) through the atrioventricular node (AVN) to the Purkyne tissue coordinates the contraction of the heart chambers, and discuss why the delay…
  46. Compare7 marksChallengeTwo blood vessels from a mammal are described below: Vessel X: Thick wall composed of three distinct layers (tunica intima, media, adventitia). Tunica media contains many layers of elastic fibres and smooth muscle…
  47. Explain6 marksChallengeIn a healthy mammalian heart, the aortic valve opens about 0.05 s after the start of ventricular systole. In a heart where the Purkyne tissue has been partially damaged, this interval increases to 0.10 s and the…
  48. Describe5 marksChallengeThe table below shows pressure changes in the left side of the heart (atrium, ventricle and aorta) during one cardiac cycle. Stage Atrial pressure / mmHg Left ventricular pressure / mmHg Aortic pressure / mmHg 1…
  49. Describe6 marksChallengeDescribe the role of the high specific heat capacity of water in the transport of heat by the blood in mammals.
  50. Explain6 marksChallengeA student makes the following statement about the cardiac cycle: "The atrioventricular valves close when ventricular pressure exceeds atrial pressure, and they open when ventricular pressure falls below atrial…
  51. Describe6 marksChallengeThe table shows the percentage saturation of adult human haemoglobin at different partial pressures of oxygen (pO2) at 37°C and pH 7.4. pO2 (kPa) Saturation (%) 2 20 4 40 6 65 8 85 12 97.5 Using the data, describe the…
  52. Explain6 marksChallengeTable 1 shows the percentage saturation of haemoglobin with oxygen at various partial pressures of oxygen (pO₂) in the blood at pH 7.4 (typical of blood in the lungs) and at pH 7.2 (typical of blood in respiring…
  53. Explain7 marksChallengeA researcher investigated carbon dioxide transport in human blood. Blood samples were taken from a volunteer at rest and immediately after 5 minutes of vigorous exercise. The concentration of chloride ions (Cl⁻) inside…
  54. Explain5 marksChallengeDuring a 10 km race, the leg muscles of an athlete receive greatly increased blood flow to meet the demand for oxygen and remove carbon dioxide and heat. (a) Explain how the structure of the blood vessels supplying the…
  55. Explain6 marksChallengeA researcher investigates the transport of carbon dioxide in human blood. She treats a sample of whole blood with an inhibitor of carbonic anhydrase and compares the amount of carbon dioxide released in the lungs to a…
  56. Explain5 marksChallengeA study of high-altitude residents (3500 m) and sea-level residents produced the following mean blood values: Parameter Sea-level High-altitude Arterial PO2 / kPa 12.5 8.0 Arterial O2 saturation / % 98 92 Arterial pH…
  57. Describe6 marksChallengeA patient’s left atrioventricular (mitral) valve fails to close completely during ventricular systole, allowing a small volume of blood to flow back into the left atrium. Describe the pressure changes that occur in the…
  58. Describe6 marksChallengeA marathon runner’s leg muscles generate large amounts of heat during a race. The blood and tissue fluid play a key role in preventing overheating. Describe how the high specific heat capacity of water contributes to…
  59. Describe7 marksChallengeDuring strenuous exercise, skeletal muscle cells respire actively, producing large amounts of carbon dioxide. Describe the transport of carbon dioxide from these muscle cells to the lungs, and explain the importance of…