plumiTransport across membranes: Edexcel International A Level Biology questions
Every Edexcel International A Level Biology exam question on Transport across membranes (specification points 2.4–2.5), 2019–2025, with its mark scheme and examiner’s report.
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Calculations
Q7(d)
The whole paper ↗Q8(e)
The whole paper ↗Q6(c)(ii)
The whole paper ↗Q3(a)
The whole paper ↗Your answerQ3(b)
The whole paper ↗Your answerQ3(c)
The whole paper ↗Your answerQ3(d)
The whole paper ↗Your answerQ3(e)
The whole paper ↗Your answerQ3(f)
The whole paper ↗Q7(c)(i)
The whole paper ↗Q9(a)(i)
The whole paper ↗Your answerQ9(a)(ii)
The whole paper ↗Q9(b)(i)
The whole paper ↗Q9(b)(ii)
The whole paper ↗Q9(b)(iii)
The whole paper ↗Q9(b)(iv)
The whole paper ↗Q9(b)(v)
The whole paper ↗Q1(b)
The whole paper ↗Q6(a)
The whole paper ↗Q6(b)
The whole paper ↗
All 55 questions on Transport across membranes, as a list
- January 2025, AS Unit 1, Q7(d) (2 marks): The Davson and Danielli model was the first to include proteins. Explain why some membrane proteins would not be able to carry out their transport functions if
- January 2025, Unit 5, Q8(e) (2 marks): Explain why ‘cells shrink a bit’ when blood electrolyte concentration increases (paragraph 21). (2)
- June 2024, AS Unit 1, Q6(c)(ii) (2 marks): The absorption of glucose into the bloodstream requires membrane transport proteins. Explain why glucose cannot diffuse into the bloodstream. (2)
- January 2024, AS Unit 1, Q3(a) (1 mark): Which pair of membrane transport mechanisms only involves a solute moving down a concentration gradient? (1) A active transport and diffusion B active transport
- January 2024, AS Unit 1, Q3(b) (1 mark): Which of the following transport mechanisms involve carrier proteins in the membrane? • active transport • diffusion • exocytosis (1) A active transport only B
- January 2024, AS Unit 1, Q3(c) (1 mark): Which cell transport mechanism is used to take large particles or bacteria into a cell? (1) A active transport B endocytosis C exocytosis D facilitated diffusio
- January 2024, AS Unit 1, Q3(d) (1 mark): Which cell transport mechanism moves small lipid-soluble molecules through the membrane? (1) A active transport B diffusion C facilitated diffusion D osmosis
- January 2024, AS Unit 1, Q3(e) (1 mark): Channel proteins are involved in facilitated diffusion. Which row of the table describes the charge on the R groups on the amino acids of a channel protein? (1)
- January 2024, AS Unit 1, Q3(f) (4 marks): A student investigated the effect of four different coloured solutions on the mass of pieces of sweet potato. Dyes were dissolved in water to produce the colour
- October 2023, AS Unit 1, Q7(c)(i) (3 marks): Explain how the LDL‑R is involved in endocytosis of LDLs. (3)
- June 2023, AS Unit 1, Q9(a)(i) (1 mark): Which row in the table identifies the marine animals P, Q and R? (1) P Q R A partial osmoconformer osmoregulator strict osmoconformer B partial osmoconformer st
- June 2023, AS Unit 1, Q9(a)(ii) (3 marks): Explain the advantages for osmoconformers of having cells with solute concentrations similar to that of the sea water they live in. (3)
- June 2023, AS Unit 1, Q9(b)(i) (1 mark): Estimate the chloride concentration of the cells of a jellyfish. (1) Answer a.u.
- June 2023, AS Unit 1, Q9(b)(ii) (2 marks): Calculate the percentage difference in the concentration of magnesium ions in the lobster compared with the sea urchin. Give your answer to two decimal places.
- June 2023, AS Unit 1, Q9(b)(iii) (2 marks): These three animals are osmoconformers even though they have different concentrations of each ion in their cells. Explain why these three animals can be describ
- June 2023, AS Unit 1, Q9(b)(iv) (1 mark): Suggest why osmoconformers do not have the same concentration of each ion in their cells. (1)
- June 2023, AS Unit 1, Q9(b)(v) (2 marks): Energy is needed to maintain the concentration of ions inside the osmoconformers. Explain what this energy is being used for. (2)
- June 2023, Unit 4, Q1(b) (4 marks): The student suggested that magnesium ions are taken up by active transport. Explain why the student came to this conclusion. Use the information in the graph to
- June 2023, Unit 5, Q6(a) (3 marks): Explain how ions can cross the cell membrane. (3)
- June 2023, Unit 5, Q6(b) (6 marks): Ions are found within fluids in the human body in different concentrations. The graph shows the concentration of ions in intracellular fluid (cytoplasm), extrac
- January 2023, AS Unit 3, Q3(a) (2 marks): State what is meant by the term water potential. (2)
- January 2023, AS Unit 3, Q3(b)(i) (2 marks): Describe how the mass could be measured in a valid and accurate way. (2) Valid Accurate
- January 2023, AS Unit 3, Q3(b)(iii) (3 marks): In this investigation, the tubes containing the cylinders and the solutions were kept at the same temperature. Explain the effect on this investigation if the y
- January 2023, AS Unit 3, Q3(c)(iii) (2 marks): Different concentrations of sucrose solutions have different water potentials. The graph shows the water potentials for sucrose solutions of different concentra
- January 2023, AS Unit 3, Q3(c)(iv) (1 mark): The water potential for the yam was –1890 kPa. Suggest why there is a difference between the water potential of the yam and the water potential of the potato. (
- October 2022, AS Unit 1, Q1(b)(i) (1 mark): How does a nonpolar molecule move through a cell membrane, down a concentration gradient into a cell? (1) A by active transport B by diffusion C by exocytosis D
- October 2022, AS Unit 1, Q1(b)(ii) (1 mark): How many of the following statements are correct for the transport of a substance by endocytosis? • transports substances out of the cell • the cell membrane su
- October 2022, Unit 4, Q5(c) (4 marks): Albumin binds to and activates a proton channel, hHv1. This proton channel is present in the membranes of sperm cells. When the channel is activated, sperm cell
- October 2022, Unit 6, Q2(a)(ii) (1 mark): Calculate the rate of diffusion per minute between 1 and 2 hours. (1) µg cm–3 min–1
- October 2022, Unit 6, Q2(a)(iii) (1 mark): The rate of diffusion between 4 and 5 hours is 0.40 µg cm–3 min–1. Calculate the percentage decrease in the rate of diffusion between 1 and 2 hours and between
- October 2022, Unit 6, Q2(a)(iv) (2 marks): Caffeine is a polar molecule. Explain the difference in the rate of diffusion between 1 and 2 hours compared with the rate of diffusion between 4 and 5 hours. (
- October 2022, Unit 6, Q2(b)(i) (2 marks): State one abiotic and one biotic variable that could affect this investigation. (2) Abiotic variable Biotic variable
- October 2022, Unit 6, Q2(b)(ii) (2 marks): Choose one of the variables you have identified in (b)(i). Describe how this variable could be controlled and the effect it could have on the results if it is n
- January 2022, AS Unit 1, Q6(a)(i) (1 mark): Which part would contain the statement: uses proteins? (1) A II B III C IV D VII
- January 2022, AS Unit 1, Q6(a)(ii) (1 mark): Which part would contain the statement: needs energy in the form of ATP? (1) A II B V C VI D VII
- January 2022, AS Unit 1, Q6(a)(iii) (1 mark): Which part would contain the statement: solutes can only move down a concentration gradient? (1) A II B III C V D VII
- January 2022, AS Unit 1, Q6(b) (3 marks): Osmosis can be defined as the movement of free water molecules through a partially permeable membrane, down a water potential gradient. Explain this definition.
- January 2022, AS Unit 1, Q6(c) (6 marks): The photograph shows a Chinese mitten crab. (Source: © WILDLIFE GmbH / Alamy Stock Photo) Mitten crabs spend most of their lives in fresh water and only return
- January 2022, AS Unit 3, Q3(a)(i) (1 mark): Suggest how the method can be modified to increase validity. (1)
- January 2022, AS Unit 3, Q3(c)(ii) (2 marks): Calculate the rate of change in length of the carrot cylinder in a 1.0 mol dm−3 solution at 15 minutes. (2) Answer mm min−1
- January 2022, AS Unit 3, Q3(c)(iii) (2 marks): Explain the results between 40 and 50 minutes for the 1.0 mol dm−3 solution. (2)
- January 2022, AS Unit 3, Q3(c)(iv) (2 marks): Explain the results between 40 and 50 minutes for the 0.0 mol dm−3 solution. (2)
- June 2021, AS Unit 1, Q8(c) (6 marks): The diagram and table give information about some molecules found inside and outside a cell. Molecule Key Description small dipolar molecule consisting of two E
- October 2020, AS Unit 3, Q1(a) (3 marks): Explain the changes that occur when the mass increases. (3)
- October 2020, AS Unit 3, Q1(b)(i) (5 marks): Describe a method that could have been used to obtain these results. (5)
- October 2020, AS Unit 3, Q1(b)(iii) (2 marks): The graph shows the water potential of different concentrations of salt solution. 0.0 0.2 0.4 0.6 0.8 1.0 0.0 –1.0 –2.0 Water potential –3.0 / MPa –4.0 –5.0 –6.
- October 2020, AS Unit 3, Q1(c) (3 marks): A scientist investigated the effect of storage time on the water potential of potato tubers. The results of this investigation are shown in the graph. 0 5 10 15
- October 2020, Unit 4, Q5(b)(i) (2 marks): Describe the role of channel proteins in the facilitated diffusion of lysins. (2)
- October 2020, Unit 6, Q1(b) (5 marks): Describe an experiment to compare the water potential of the tissue from these two types of tuber. (5)
- October 2020, Unit 6, Q1(d) (3 marks): Explain the factors that may affect the water potential of potato cells. (3)
- January 2020, AS Unit 1, Q5(a)(i) (2 marks): Explain why water enters the paramecium. (2)
- January 2020, AS Unit 1, Q5(a)(ii) (3 marks): Explain the importance of the contractile vacuole in the paramecium. (3)
- January 2020, AS Unit 1, Q5(b) (6 marks): In an investigation, paramecia were placed in three separate solutions: pond water, solution A and solution B. The paramecia were observed using a light microsc
- June 2019, AS Unit 1, Q5(b)(ii) (6 marks): Pineapples can be preserved by a process called osmotic dehydration in which pieces of pineapple are submerged in a solution of sugars. The diagram shows how th
- January 2019, AS Unit 1, Q5(b)(i) (1 mark): How does glycerol pass through the liposome membrane? (1) A active transport B diffusion C endocytosis D osmosis
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