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Stimuli, both internal and external, are detected and lead to a response: AQA A‑Level Biology questions

Every AQA A-Level Biology exam question on 3.6.1 Stimuli, both internal and external, are detected and lead to a response, 2016–2025, with its mark scheme and examiner’s report.

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1,383 questions

  1. Q06.3

    June 2025 · Paper 2

    3 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2025 Paper 2, question 06.3: The parasympathetic nervous system (PNS) uses acetylcholine as its neurotransmitter. Atropine is an anticholinergic drug that attaches to postsynaptic receptors

  2. Q06.4

    June 2025 · Paper 2

    2 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2025 Paper 2, question 06.4: One study has suggested that the atropine dosage for severely obese male patients should be 0.01 mg kg–1 of lean body weight (LBW). LBW is determined by using t

  3. Q07.1

    June 2025 · Paper 2

    3 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2025 Paper 2, question 07.1: Figure 3 shows Gammarus pulex, commonly known as a freshwater shrimp. Figure 3 A student used a choice chamber to investigate the effect of light intensity on t

  4. Q07.2

    June 2025 · Paper 2

    2 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2025 Paper 2, question 07.2: Table 3 shows the student’s results. Table 3 Segment of choice chamber Percentage light intensity Number of G. pulex counted after 10 minutes A 0 15 B 25 8 C 50

  5. Q07.3

    June 2025 · Paper 2

    2 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2025 Paper 2, question 07.3: Table 4 Critical values of χ2 at different P values Degrees of freedom P = 0.95 P = 0.5 P = 0.05 P = 0.01 P = 0.005 1 0.00 0.46 3.84 6.64 7.88 2 0.10 1.39 5.99

  6. Q07.4

    June 2025 · Paper 2

    4 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2025 Paper 2, question 07.4: Using the calculated χ2 value of 11.87 and the information in Table 4, what can you conclude from this investigation? You should include the terms probability a

  7. Q07.2

    June 2025 · Paper 3

    25 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response3.6.4 Homeostasis is the maintenance of a stable internal environment
    The whole paper ↗
    June 2025 Paper 3, question 07.2: The importance of responses to changes in the internal and external environment of organisms. [25 marks]

  8. Q06.1

    June 2024 · Paper 2

    5 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2024 Paper 2, question 06.1: Describe the myogenic stimulation of the heart and how the regular contraction of the atria and ventricles is coordinated. Do not include the autonomic nervous

  9. Q06.2

    June 2024 · Paper 2

    3 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2024 Paper 2, question 06.2: Atrial fibrillation (AF) is a condition that causes an irregular heart rate. Scientists used a statistical test to investigate the association between different

  10. Q08.1

    June 2024 · Paper 2

    2 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2024 Paper 2, question 08.1: Use the information provided to explain the relationship between IAA concentration, cell wall plasticity and mean growth of the stem segments. [2 marks]

  11. Q08.2

    June 2024 · Paper 2

    2 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2024 Paper 2, question 08.2: Use Figure 6 to calculate the percentage increase in mean growth of the stem segments when the IAA concentration was increased from 10–8 mol dm–3 to 10–5 mol dm

  12. Q08.3

    June 2024 · Paper 2

    1 mark3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2024 Paper 2, question 08.3: A technician produced the different concentrations of GA solution from a stock 10–1 mol dm–3 concentration of GA. Describe how the technician produced the 10–3

  13. Q08.4

    June 2024 · Paper 2

    5 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2024 Paper 2, question 08.4: Describe a suitable procedure the student could follow to investigate the effect of different concentrations of GA on the growth of stem segments. In your answe

  14. Q05.1

    June 2023 · Paper 2

    3 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2023 Paper 2, question 05.1: Figure 3 shows the wavelengths of light absorbed by three types of photoreceptor found in the human retina. Figure 3 Use Figure 3 and your knowledge of colour v

  15. Q05.2

    June 2023 · Paper 2

    1 mark3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2023 Paper 2, question 05.2: Which of the following statements is associated with high sensitivity to light in the retina? Tick () one box. [1 mark] A single photoreceptor connecting to on

  16. Q10.5

    June 2023 · Paper 2

    4 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    June 2023 Paper 2, question 10.5: An increase in muscle activity causes an increase in heart rate (lines 12–14). Describe and explain how. [4 marks]

  17. Q03.1

    November 2021 · Paper 2

    3 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    November 2021 Paper 2, question 03.1: Use your knowledge of indoleacetic acid (IAA) to explain the growth curvature shown in Figure 1. [3 marks]

  18. Q03.2

    November 2021 · Paper 2

    5 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    November 2021 Paper 2, question 03.2: Using the procedure in Figure 2 and the calibration curve in Figure 3, describe how you could compare the IAA concentration in shoot tips from two different pla

  19. Q03.3

    November 2021 · Paper 2

    2 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    November 2021 Paper 2, question 03.3: State two conclusions about IAA that you can make from the results shown in Table 1. [2 marks] 1 2

  20. Q03.1

    November 2021 · Paper 3

    2 marks3.6.1 Stimuli, both internal and external, are detected and lead to a response
    The whole paper ↗
    November 2021 Paper 3, question 03.1: Name the type of behaviour shown by beetles G, J, P and R, and suggest one advantage to adult beetles of the type of behaviour shown. [2 marks] Behaviour Advant
All 43 questions on Stimuli, both internal and external, are detected and lead to a response, as a list
  1. June 2025, Paper 2, Q06.3 (3 marks): The parasympathetic nervous system (PNS) uses acetylcholine as its neurotransmitter. Atropine is an anticholinergic drug that attaches to postsynaptic receptors
  2. June 2025, Paper 2, Q06.4 (2 marks): One study has suggested that the atropine dosage for severely obese male patients should be 0.01 mg kg–1 of lean body weight (LBW). LBW is determined by using t
  3. June 2025, Paper 2, Q07.1 (3 marks): Figure 3 shows Gammarus pulex, commonly known as a freshwater shrimp. Figure 3 A student used a choice chamber to investigate the effect of light intensity on t
  4. June 2025, Paper 2, Q07.2 (2 marks): Table 3 shows the student’s results. Table 3 Segment of choice chamber Percentage light intensity Number of G. pulex counted after 10 minutes A 0 15 B 25 8 C 50
  5. June 2025, Paper 2, Q07.3 (2 marks): Table 4 Critical values of χ2 at different P values Degrees of freedom P = 0.95 P = 0.5 P = 0.05 P = 0.01 P = 0.005 1 0.00 0.46 3.84 6.64 7.88 2 0.10 1.39 5.99
  6. June 2025, Paper 2, Q07.4 (4 marks): Using the calculated χ2 value of 11.87 and the information in Table 4, what can you conclude from this investigation? You should include the terms probability a
  7. June 2025, Paper 3, Q07.2 (25 marks): The importance of responses to changes in the internal and external environment of organisms. [25 marks]
  8. June 2024, Paper 2, Q06.1 (5 marks): Describe the myogenic stimulation of the heart and how the regular contraction of the atria and ventricles is coordinated. Do not include the autonomic nervous
  9. June 2024, Paper 2, Q06.2 (3 marks): Atrial fibrillation (AF) is a condition that causes an irregular heart rate. Scientists used a statistical test to investigate the association between different
  10. June 2024, Paper 2, Q08.1 (2 marks): Use the information provided to explain the relationship between IAA concentration, cell wall plasticity and mean growth of the stem segments. [2 marks]
  11. June 2024, Paper 2, Q08.2 (2 marks): Use Figure 6 to calculate the percentage increase in mean growth of the stem segments when the IAA concentration was increased from 10–8 mol dm–3 to 10–5 mol dm
  12. June 2024, Paper 2, Q08.3 (1 mark): A technician produced the different concentrations of GA solution from a stock 10–1 mol dm–3 concentration of GA. Describe how the technician produced the 10–3
  13. June 2024, Paper 2, Q08.4 (5 marks): Describe a suitable procedure the student could follow to investigate the effect of different concentrations of GA on the growth of stem segments. In your answe
  14. June 2023, Paper 2, Q05.1 (3 marks): Figure 3 shows the wavelengths of light absorbed by three types of photoreceptor found in the human retina. Figure 3 Use Figure 3 and your knowledge of colour v
  15. June 2023, Paper 2, Q05.2 (1 mark): Which of the following statements is associated with high sensitivity to light in the retina? Tick () one box. [1 mark] A single photoreceptor connecting to on
  16. June 2023, Paper 2, Q10.5 (4 marks): An increase in muscle activity causes an increase in heart rate (lines 12–14). Describe and explain how. [4 marks]
  17. November 2021, Paper 2, Q03.1 (3 marks): Use your knowledge of indoleacetic acid (IAA) to explain the growth curvature shown in Figure 1. [3 marks]
  18. November 2021, Paper 2, Q03.2 (5 marks): Using the procedure in Figure 2 and the calibration curve in Figure 3, describe how you could compare the IAA concentration in shoot tips from two different pla
  19. November 2021, Paper 2, Q03.3 (2 marks): State two conclusions about IAA that you can make from the results shown in Table 1. [2 marks] 1 2
  20. November 2021, Paper 3, Q03.1 (2 marks): Name the type of behaviour shown by beetles G, J, P and R, and suggest one advantage to adult beetles of the type of behaviour shown. [2 marks] Behaviour Advant
  21. November 2021, Paper 3, Q03.2 (3 marks): After studying these experiments, a student concluded: • there is a significant change in movement between 35 °C and 37.5 °C • between 35 °C and 37.5 °C, more b
  22. November 2020, Paper 2, Q01.1 (2 marks): Suggest and explain how the interaction between the muscles labelled in Figure 1 could cause the pupil to constrict (narrow). [2 marks]
  23. November 2020, Paper 2, Q01.2 (3 marks): The fovea of the eye of an eagle has a high density of cones. An eagle focuses the image of its prey onto the fovea. Explain how the fovea enables an eagle to s
  24. November 2020, Paper 2, Q01.3 (2 marks): The retina of the human eye has an area of approximately 1.094 × 103 mm2 The circular fovea in a human eye has a diameter of 3 × 103 µm Calculate the area of th
  25. November 2020, Paper 2, Q01.4 (3 marks): The retina of an owl has a high density of rod cells. Explain how this enables an owl to hunt its prey at night. Do not refer to rhodopsin in your answer. [3 ma
  26. November 2020, Paper 2, Q10.2 (4 marks): During hibernation, the heart rate and the metabolic rate of black bears decrease (lines 3−5). Use your knowledge of the nervous control of heart rate to descri
  27. June 2019, Paper 2, Q03.1 (2 marks): Explain why the student removed the shoot tip from each seedling. [2 marks] [ ]
  28. June 2019, Paper 2, Q03.2 (2 marks): Explain why the student added glucose solution to each Petri dish. [2 marks]
  29. June 2019, Paper 2, Q03.3 (2 marks): Explain why the lids were kept on the Petri dishes. [2 marks]
  30. June 2019, Paper 2, Q03.4 (3 marks): Describe and explain the results shown in Table 1 and suggest how the results might have differed if lengths of root had been used. [3 marks]
  31. June 2019, Paper 2, Q03.5 (1 mark): The student produced the different concentrations of IAA using a stock 1 g dm–3 solution of IAA (1 g dm–3 = 1 part per thousand) and distilled water. Complete T
  32. June 2019, Paper 2, Q10.2 (3 marks): Sometimes Guillain–Barré syndrome causes heart rate irregularities (lines 4–5). Suggest and explain why. [3 marks]
  33. June 2019, Paper 3, Q03.4 (2 marks): Caffeine affects the autonomic nervous system. Suggest how caffeine could account for the results of Group I in Figure 3 at 60 minutes. [2 marks]
  34. June 2019, Paper 3, Q03.6 (2 marks): The increase seen in Group I could be due to the combination of caffeine and sugar. Suggest one drink to be given to an additional group that should be investig
  35. June 2019, Paper 3, Q05.1 (1 mark): State a null hypothesis the marine biologists tested in this investigation. [1 mark]
  36. June 2019, Paper 3, Q05.2 (1 mark): The natural habitat of COTS is coral reefs of tropical oceans. Suggest two factors that should be kept constant in the choice chambers so that COTS display norm
  37. June 2019, Paper 3, Q05.3 (3 marks): A journalist studying Table 1 suggested that either type of light could be used to cause COTS to move away from coral reefs. Evaluate the journalist’s suggestio
  38. June 2019, Paper 3, Q05.4 (2 marks): One of the reasons COTS can destroy coral reefs in a short time is because COTS move quickly, allowing them to move from one reef to another. Table 2 shows the
  39. June 2018, Paper 2, Q10.1 (3 marks): 1 0 Read the following passage. Complete achromatopsia is a form of complete colour blindness. It is caused by having only rods and no functional cone cells. Pe
  40. June 2018, Paper 2, Q10.4 (3 marks): 1 0 Read the following passage. Complete achromatopsia is a form of complete colour blindness. It is caused by having only rods and no functional cone cells. Pe
  41. June 2017, Paper 2, Q01.1 (4 marks): Exercise causes an increase in heart rate. Describe the role of receptors and of the nervous system in this process. [4 marks]
  42. Specimen, Paper 3, Q06.1 (25 marks): Write an essay on one of the topics below. EITHER 6 The importance of movement in living organisms. [25 marks] OR 0 6 . 1
  43. Specimen, Paper 3, Q06.2 (25 marks):

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