plumiSynapses and drugs: Edexcel International A Level Biology questions
Every Edexcel International A Level Biology exam question on Synapses and drugs (specification points 8.6–8.7), 2019–2025, with its mark scheme and examiner’s report.
Paper
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Calculations
Q3(a)
The whole paper ↗Your answerQ3(b)
The whole paper ↗Your answerQ3(c)
The whole paper ↗Q3(d)(i)
The whole paper ↗Q3(d)(ii)
The whole paper ↗Q4(a)
The whole paper ↗Q6(a)
The whole paper ↗Your answerQ6(b)(i)
The whole paper ↗Q6(b)(iii)
The whole paper ↗Q8(b)
The whole paper ↗Q4(a)
The whole paper ↗Q4(b)
The whole paper ↗Q4(c)
The whole paper ↗Q2(b)(i)
The whole paper ↗Your answerQ2(b)(ii)
The whole paper ↗Q4(b)
The whole paper ↗Q2(a)
The whole paper ↗Q2(b)(ii)
The whole paper ↗Your answerQ2(b)(iii)
The whole paper ↗Q5(a)
The whole paper ↗
All 47 questions on Synapses and drugs, as a list
- June 2025, Unit 5, Q3(a) (1 mark): Which describes the effect lidocaine has on the membranes of neurones? (1) A it closes sodium ion channels B it increases the number of action potentials C it o
- June 2025, Unit 5, Q3(b) (1 mark): Which describes the effect of MDMA (ecstasy) on neurones? (1) A it damages the myelin sheath of neurones B it decreases the release of neurotransmitters C it de
- June 2025, Unit 5, Q3(c) (3 marks): The photograph shows a puffer fish. (Source: © ImageBROKER on Offset / Shutterstock) Tetrodotoxin (TTX) is a toxin found in puffer fish. This toxin works by bin
- June 2025, Unit 5, Q3(d)(i) (1 mark): The LD50 obtained from this graph is 8.4 μg kg–1. Give the meaning of LD50 = 8.4 μg kg–1. Use the information in the graph to support your answer. (1)
- June 2025, Unit 5, Q3(d)(ii) (3 marks): Comment on the toxicity of TTX in mice. (3)
- June 2025, Unit 5, Q4(a) (4 marks): Parkinson’s disease arises from decreased dopamine production in the brain. Explain why L-Dopa, given orally in tablet form, reduces the symptoms of Parkinson’s
- January 2025, Unit 5, Q6(a) (1 mark): Which chemical would increase the likelihood of a nerve impulse being initiated at a post‑synaptic membrane? (1) A auxin B dopamine C gibberellin D statin
- January 2025, Unit 5, Q6(b)(i) (3 marks): Assess the effects of lidocaine on cell survival. (3)
- January 2025, Unit 5, Q6(b)(iii) (2 marks): Suggest how lidocaine protects heart muscle cells from effects of low oxygen. (2)
- January 2025, Unit 5, Q8(b) (3 marks): Caffeine is a naturally occurring stimulant of the central nervous system. Explain how caffeine present in an energy drink can affect the cells of the brain (pa
- October 2024, Unit 5, Q4(a) (4 marks): In people without Parkinson’s disease, the number of dopamine‑producing cells rarely falls below 350 000. Explain why the symptoms of Parkinson’s disease increa
- October 2024, Unit 5, Q4(b) (2 marks): The drug L‑DOPA is used in tablet form to treat Parkinson’s disease. This drug is converted to dopamine by an enzyme found in the digestive system and the brain
- October 2024, Unit 5, Q4(c) (4 marks): In an investigation, different concentrations of dopamine were given to Drosophila (fruit flies). The mean heart rates of groups of 10 Drosophila were recorded
- June 2024, Unit 5, Q2(b)(i) (1 mark): Which of the following statements about dopamine is correct? (1) A dopamine can pass from the bloodstream into neurones in the brain B dopamine is a neurotransm
- June 2024, Unit 5, Q2(b)(ii) (3 marks): Drugs called selective serotonin re-uptake inhibitors (SSRIs) affect the reabsorption of serotonin at synapses in the brain. This may help to reduce depression.
- January 2024, Unit 5, Q4(b) (4 marks): Scientists used three groups of mice (A, B and C) to investigate the effect of nicotine on the transmission of nerve impulses. • Group A were given nicotine • G
- October 2023, Unit 5, Q2(a) (4 marks): Describe how the pupil of an eye dilates and contracts in response to changes in light intensity. (4)
- October 2023, Unit 5, Q2(b)(ii) (1 mark): Which of these drugs would increase nerve transmission? (1) A ecstasy (MDMA) and lidocaine B ecstasy (MDMA) and nicotine C lidocaine and nicotine D lidocaine on
- October 2023, Unit 5, Q2(b)(iii) (2 marks): In direct sunlight the diameter of the pupil was 4 mm. In complete darkness the area of the pupil was 38.75 mm2. Calculate the increase in diameter of the pupil
- October 2023, Unit 5, Q5(a) (4 marks): Describe how a neurotransmitter allows an impulse to be transferred to an adjacent neurone. (4)
- October 2023, Unit 5, Q6(a)(ii) (3 marks): Nicotine is a drug found in tobacco products. The effect of changing the concentration of nicotine and adrenaline on the mean heart rate of Daphnia was investig
- June 2023, Unit 5, Q1(a) (1 mark): The table shows the mean pupil diameter in different light intensities. Light intensity Pupil diameter / mm bright light 3.35 normal room light 3.86 darkness 6.
- June 2023, Unit 5, Q1(b)(ii) (3 marks): Describe how this change in diameter is brought about by the muscles of the iris. (3)
- June 2023, Unit 5, Q7(a) (1 mark): How many of the following statements about serotonin are correct? (1) • L-dopa can be converted into serotonin in the brain • Serotonin is a neurotransmitter •
- June 2023, Unit 5, Q7(c)(i) (2 marks): Determine the effect of MDMA on the serotonin level in the cerebrospinal fluid. (2)
- June 2023, Unit 5, Q7(c)(ii) (2 marks): Predict the concentration of serotonin for a dose of 17.5 mg kg–1 of MDMA. Use the line of best fit. Give your answer in g cm–3. (2) g cm–3
- June 2023, Unit 5, Q7(c)(iii) (3 marks): Explain how the MDMA taken by mouth could affect the level of serotonin in the brain. Use the information in the question to support your answer. (3)
- January 2023, Unit 5, Q3(c) (4 marks): Explain how the nerve impulse is transmitted across a synapse. (4)
- January 2023, Unit 5, Q7(a)(i) (4 marks): Comment on the results shown in the bar chart and how they support this conclusion. (4)
- January 2023, Unit 5, Q7(a)(ii) (2 marks): The table gives the results for a sucrose concentration of 0.4 mol dm–3. Complete the table to calculate the standard deviation (S) for these results. 2 x x S =
- October 2022, Unit 5, Q3(a)(ii) (1 mark): Lidocaine is a drug that is used as a local anaesthetic. Lidocaine works by (1) A blocking the binding of acetylcholine to its receptor B blocking the release o
- June 2022, Unit 5, Q4(a) (3 marks): Explain why using Co‑beneldopa will be more effective than using L‑dopa alone to treat Parkinson’s disease. (3)
- June 2022, Unit 5, Q5(c) (4 marks): Mutations in the genes coding for voltage‑gated calcium ion channels have been linked to neurological conditions. Explain how these mutations might cause these
- June 2022, Unit 5, Q8(b) (3 marks): Explain how neurones can respond to different neurotransmitter substances (paragraph 4). (3)
- January 2022, Unit 5, Q6(a) (1 mark): Which substance can transmit a nerve impulse from one neurone to the next one? (1) A acetylcholine B ADP C cholesterol D NADP
- October 2021, Unit 5, Q3(c) (1 mark): Which statement describes the response of the muscles in the iris to increasing light intensity? (1) A circular and radial muscles contract B circular and radia
- June 2021, Unit 5, Q7(a)(i) (3 marks): The size of the pupil changes when moving from dim to very bright light. Explain how this change occurs. (3)
- January 2021, Unit 5, Q7(a)(i) (4 marks): Describe how a neurotransmitter transmits a nerve impulse across a synapse. (4)
- January 2021, Unit 5, Q7(a)(ii) (3 marks): One treatment for Parkinson’s disease is a drug called L-DOPA. Describe how L-DOPA reduces some of the symptoms of Parkinson’s disease. (3)
- January 2021, Unit 5, Q7(b)(ii) (3 marks): Some people with Parkinson’s disease have a DNA mutation called LRRK2. Scientists studied the effect of this mutation on the dendrites of dopamine neurones prod
- October 2020, Unit 5, Q3(a)(i) (1 mark): Estimate how long it takes the MDMA concentration in the blood to become 0.0 µg dm−3. (1) Answer hours
- October 2020, Unit 5, Q5(a)(i) (2 marks): Describe the relationship between light intensity and pupil diameter. (2)
- October 2020, Unit 5, Q5(a)(ii) (3 marks): Calculate the amount of incandescent light that can pass through the pupil when the light intensity is 1400 a.u. per m2. Use a value of pi (π) = 3.14 (3) Answer
- October 2020, Unit 5, Q5(a)(iii) (4 marks): Describe how light entering the eye causes the pupil to respond. (4)
- October 2020, Unit 5, Q7(a)(i) (1 mark): One drug used to treat Parkinson’s disease is L-DOPA. Which of the following statements explains why L-DOPA can be used to treat Parkinson’s disease? (1) A L-DO
- October 2020, Unit 5, Q7(a)(ii) (3 marks): Explain why the release of reduced quantities of dopamine by presynaptic neurones could result in motor symptoms. (3)
- October 2020, Unit 5, Q7(b) (2 marks): It has been suggested that in Parkinson’s disease dopamine-producing neurones die because of a failure to release dopamine. Suggest how the release of dopamine
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