plumiEnzymes: Edexcel A‑Level Biology B questions
Every Edexcel A-Level Biology B exam question on 1.5 Enzymes, 2016–2025, with its mark scheme and examiner’s report.
Find questions1,826
Calculations
Q7(a)(i)
The whole paper ↗
Q7(a)(ii)
The whole paper ↗
Q7(b)(i)
The whole paper ↗
Q7(b)(ii)
The whole paper ↗
Q6(c)
The whole paper ↗
Q8(b)(i)
The whole paper ↗
Q8(b)(ii)
The whole paper ↗
Q8(b)(iii)
The whole paper ↗
Q8(c)
The whole paper ↗
Q8(d)(i)
The whole paper ↗
Q8(d)(ii)
The whole paper ↗
Q1(c)
The whole paper ↗
Q10(b)
The whole paper ↗
Q6(b)
The whole paper ↗
Q2(b)(i)
The whole paper ↗
Q2(b)(ii)
The whole paper ↗
Q2(a)
The whole paper ↗
Q2(b)
The whole paper ↗
Q2(c)(i)
The whole paper ↗
Q2(c)(ii)
The whole paper ↗
All 86 questions on Enzymes, as a list
- June 2025, Paper 3, Q7(a)(i) (2 marks): Describe how you would ensure that the concentration of the enzyme extract was the same for all students carrying out the investigation. (2)
- June 2025, Paper 3, Q7(a)(ii) (2 marks): Describe how you would ensure that the colorimeter readings were comparable for each of the students. (2)
- June 2025, Paper 3, Q7(b)(i) (3 marks): Explain the effect of temperature on the activity of phosphatase. (3)
- June 2025, Paper 3, Q7(b)(ii) (4 marks): For enzyme-controlled reactions at temperatures between 0°C and 40°C, a 10°C rise in temperature will double the rate of reaction. The data collected in this in
- June 2025, AS Paper 1, Q6(c) (2 marks): In another investigation, the rate of pollen tube growth at different temperatures was determined. The graph shows the results of this investigation. 7 6 5 4 Ra
- June 2025, AS Paper 1, Q8(b)(i) (1 mark): Which arrow shows the activation energy for this reaction? (1) A P B Q C R D S
- June 2025, AS Paper 1, Q8(b)(ii) (1 mark): Which row of the table identifies the molecule present at time Y and the molecule present at time Z on this graph? (1) Time Y Time Z A the product threonine the
- June 2025, AS Paper 1, Q8(b)(iii) (1 mark): Which row of the table shows the change in length of the arrows P and Q on this graph in the absence of the enzyme threonine deaminase? (1) Change in length of
- June 2025, AS Paper 1, Q8(c) (3 marks): Explain why the conversion of threonine to isoleucine involves several different enzymes. (3)
- June 2025, AS Paper 1, Q8(d)(i) (3 marks): Explain how end‑product inhibition affects this reaction. (3)
- June 2025, AS Paper 1, Q8(d)(ii) (3 marks): Complete the graph to show how the concentration of isoleucine would change as a result of end‑product inhibition of threonine deaminase. (3) Concentration of i
- June 2024, Paper 2, Q1(c) (2 marks): Some plants have adaptations that prevent them being eaten by animals. Sorghum is a plant that stores a substance called dhurrin inside leaf cells in the struct
- June 2024, Paper 3, Q10(b) (3 marks): The experiment with sucrose was repeated at a temperature 10°C lower. All other variables remained the same. Explain the effect of this temperature change on th
- June 2024, AS Paper 1, Q6(b) (3 marks): Neuraminidase is an enzyme. Describe the structure of an enzyme. (3)
- June 2023, Paper 1, Q2(b)(i) (3 marks): The tertiary structures of AK1 and AK3 are very similar but not identical. Analyse the information to deduce why there are two AK enzymes. (3)
- June 2023, Paper 1, Q2(b)(ii) (2 marks): Some types of Archaea have only one type of AK enzyme. This enzyme can catalyse both the reactions shown in the table. The tertiary structure of this enzyme is
- June 2023, Paper 2, Q2(a) (1 mark): Which graph shows the energy changes that occur in a typical enzyme catalysed reaction? (1) Key: without enzyme with enzyme energy energy time time W X energy e
- June 2023, Paper 2, Q2(b) (3 marks): A student investigated the digestion of gelatine protein by pineapple juice. This is the method used. Step 1: Make a solid disc of gelatine protein, with a dept
- June 2023, Paper 2, Q2(c)(i) (2 marks): Explain the effect of increasing substrate concentration on the rate of digestion of the soluble protein. (2)
- June 2023, Paper 2, Q2(c)(ii) (2 marks): Explain the effect of copper sulfate on the rate of digestion of the soluble protein. (2)
- June 2023, Paper 3, Q10(c)(ii) (2 marks): Explain why decreasing the temperature affects the rate of respiration of maggots. (2)
- June 2023, AS Paper 1, Q8(a) (2 marks): Polyesters account for 15 % of the 25.8 million US tons of plastic waste accumulated in Europe. Calculate the mass, in kilograms, of polyester in this accumulat
- June 2023, AS Paper 1, Q8(b) (1 mark): State why scientists think that these bacteria might be able to break down polyesters. (1)
- June 2023, AS Paper 1, Q8(c) (2 marks): The bacteria were incubated with polyester at 40 °C in a pH 7 buffer solution. Explain why these conditions were used. (2)
- June 2023, AS Paper 1, Q8(d)(i) (3 marks): Analyse the data to comment on these results. (3)
- June 2023, AS Paper 1, Q8(d)(ii) (5 marks): Devise an experiment to confirm these results. (5)
- June 2023, AS Paper 1, Q8(e) (2 marks): In another study, scientists measured the concentration of the breakdown products from two types of polyester, P1 and P2, using bacteria. The table shows the re
- June 2022, Paper 3, Q8(a) (3 marks): Explain why increasing the temperature of an enzyme-controlled reaction changes the rate of reaction. (3)
- June 2022, Paper 3, Q8(b)(i) (4 marks): Describe how two named variables, other than the potato, can be controlled in order to obtain valid results. (4)
- June 2022, Paper 3, Q8(b)(ii) (1 mark): The graph shows the results of the investigation. 50 45 40 35 30 Volume of oxygen produced / cm3 25 20 15 10 5 0 0 30 60 90 120 150 180 210 240 270 300 Time / s
- June 2022, Paper 3, Q8(b)(iii) (2 marks): Explain why the rate of reaction decreases over time. (2)
- June 2022, Paper 3, Q8(c) (3 marks): The student used this apparatus to investigate the effect of using increasing numbers of potato cubes on the rate of reaction. The potato was cut into 1 cm3 cub
- November 2021, Paper 1, Q2(b) (2 marks): Explain the results for the yeast cultured with lactose. (2)
- November 2021, Paper 3, Q6(a)(i) (5 marks): Analyse the information to explain how the activity of the enzyme acetyl CoA carboxylase is controlled. (5)
- November 2021, Paper 3, Q6(a)(ii) (2 marks): Explain why inhibitors of this enzyme may be useful in treating obesity in humans. (2)
- November 2021, Paper 3, Q6(b) (2 marks): The enzyme acetyl CoA carboxylase has a different structure in bacteria. The enzyme in bacteria is made of several polypeptide subunits whereas in humans, the e
- November 2021, Paper 3, Q8(a) (6 marks): Devise an investigation to find the optimum temperature for the activity of the enzyme cysteine protease found in pineapples. (6)
- November 2021, Paper 3, Q11(b)(ii) (4 marks): Nitrogen is a relatively unreactive gas that forms 80% of the atmosphere. The enzyme nitrogenase catalyses the reaction shown: N2 + 8H+ + 16 ATP → 2NH3 + H2 + 1
- November 2021, AS Paper 1, Q7(b)(i) (2 marks): When measuring the activity of enzymes, the initial rate of reaction should be measured. Explain why the initial rate of reaction should be measured. (2)
- November 2021, AS Paper 1, Q7(b)(ii) (6 marks): Devise an investigation, using this apparatus, to show that as sweet red peppers ripen the activity of catalase decreases. (6)
- October 2020, Paper 2, Q2(b)(i) (2 marks): Explain why DFP inhibits the activity of acetylcholinesterase. (2)
- October 2020, Paper 3, Q2(b) (5 marks): Pepsin is an enzyme that digests albumin. Albumin can be put into a 50 mm long capillary tube and then made solid by boiling in water for 10 minutes. The diagra
- October 2020, Paper 3, Q4(a) (3 marks): Explain how these results show that enzymes are involved in blood clotting. (3)
- October 2020, AS Paper 1, Q4(b) (4 marks): Catalase is an enzyme found in potato cells. It catalyses the breakdown of hydrogen peroxide. catalase hydrogen peroxide water + oxygen In an investigation, cyl
- October 2020, AS Paper 1, Q8(a) (2 marks): Calculate the initial rate of reaction at 55 °C in mmol dm–3 min–1. (2) Answer
- October 2020, AS Paper 1, Q8(b) (2 marks): Explain the difference between the two curves from 4 and 6 hours. (2)
- October 2020, AS Paper 1, Q8(c)(i) (3 marks): Analyse the information to explain why the initial rate of this reaction was faster at 65 °C than it was at 55 °C. (3)
- October 2020, AS Paper 1, Q8(d) (6 marks): Evaluate the method used in this investigation and suggest improvements. (6)
- June 2019, Paper 2, Q1(b)(ii) (3 marks): Explain why the cooler regions of a Siamese cat have dark coloured fur and the warmer regions have lighter coloured fur. (3)
- June 2019, Paper 3, Q5(a) (3 marks): Explain why no oxygen was produced when boiled liver was added to the hydrogen peroxide. (3)
- June 2019, Paper 3, Q5(b) (2 marks): Explain why it was important to measure the volume of oxygen in the first 10 seconds. (2)
- June 2019, Paper 3, Q5(c) (4 marks): The results for the volume of oxygen collected by each student using raw liver were different. Give four possible improvements to the method used by these stude
- June 2019, AS Paper 1, Q3(b) (1 mark): The chemical mercaptoethanol breaks disulfide bonds. The graph shows the initial rate of reaction of RNase with no added mercaptoethanol. Sketch a line on the g
- June 2019, AS Paper 1, Q3(c) (3 marks): Analyse the information to explain the effect of adding mercaptoethanol on the activity of RNase. (3)
- June 2019, AS Paper 1, Q5(c)(i) (2 marks): Explain how the contents of the small intestine in a patient with pancreatitis would differ from the contents of the small intestine in a healthy person. (2)
- June 2019, AS Paper 1, Q5(c)(ii) (2 marks): Some of the enzymes are produced in an inactive form. In patients with pancreatitis, these enzymes can become active in the pancreas. Explain how this activatio
- June 2019, AS Paper 1, Q7(a)(i) (2 marks): Explain why the addition of citric acid prevents the browning of apple slices. (2)
- June 2019, AS Paper 1, Q7(a)(ii) (2 marks): Explain why the addition of a protease enzyme prevents the browning of apple slices. (2)
- June 2019, AS Paper 1, Q7(b)(i) (3 marks): Analyse the data to explain the results of this investigation. (3)
- June 2019, AS Paper 1, Q7(b)(ii) (6 marks): The temperature at which apple slices are stored can affect the activity of the enzyme polyphenol oxidase. Devise a valid method to investigate the effect of te
- June 2018, Paper 1, Q1(a)(i) (1 mark): Which is a correct statement about enzymes? (1) A enzymes decrease the activation energy of metabolic reactions and decrease reaction time B enzymes decrease
- June 2018, Paper 1, Q3(b) (4 marks): Mayflies lay their eggs in water. The graph shows the effect of water temperature on the percentage of mayfly eggs that hatch. 100 – 90 – 80 – 70 – 60 – 50 – 40
- June 2018, Paper 1, Q4(c)(i) (1 mark): This sample of mitochondria had an absorbance of 0.28 when the protein concentration was measured. Determine the protein concentration of this sample of mitocho
- June 2018, Paper 1, Q4(c)(ii) (2 marks): Determine the initial rate of enzyme activity to obtain the protein : enzyme activity ratio for this sample of mitochondria. (2) Ratio
- June 2018, Paper 2, Q2(c)(i) (2 marks): Compare and contrast the effects of these two inhibitors on amylase activity. (2)
- June 2018, Paper 2, Q2(c)(ii) (3 marks): Explain which of the two inhibitors is non-competitive. (3)
- June 2018, Paper 3, Q3(b)(ii) (1 mark): A student investigated the activity of glucose isomerase. The graph shows the results of this investigation. 10 9 8 7 6 5 4 3 2 1 0 0 50 100 150 200 250 Time /
- June 2018, Paper 3, Q3(b)(iii) (5 marks): Cofactors are non-protein molecules that help enzymes to function. Magnesium ions act as cofactors for some enzymes. Devise an experiment to investigate the eff
- June 2018, AS Paper 1, Q2(a)(i) (1 mark): Which graph shows the results of this investigation? (1) A Time taken Temperature B Time taken Temperature C Time taken Temperature D Time taken Temperature
- June 2018, AS Paper 1, Q2(a)(ii) (1 mark): The graph shows the energy changes during a reaction with and without an enzyme. reaction without Z enzyme Y Energy reaction with enzyme X Progress of reaction
- June 2018, AS Paper 1, Q3(b) (3 marks): Hirudin is an inhibitor that forms hydrogen bonds with an enzyme. Explain how hirudin would inhibit the activity of the enzyme. (3)
- June 2018, AS Paper 1, Q5(b)(ii) (3 marks): Explain why the misfolded protein cannot be digested by some protease enzymes. (3)
- June 2018, AS Paper 1, Q9(a)(i) (3 marks): Calculate the mean rate of milk clotting at a chymosin concentration of 0.5%. (3) Answer min−1
- June 2018, AS Paper 1, Q9(a)(ii) (1 mark): Give one reason why the information in the table is insufficient to conclude which concentration of chymosin would be best for cheese production. (1)
- June 2018, AS Paper 1, Q9(b) (2 marks): The chymosin used for the investigation costs 3.6p to treat 100 cm3 of milk. Calculate how much it would cost to treat 200 dm3 milk. (2) Answer £
- June 2018, AS Paper 1, Q9(c) (4 marks): Devise a valid investigation to compare the effect of chymosin on the clotting time of milk from two different breeds of cattle. (4)
- June 2017, Paper 2, Q9(a)(i) (3 marks): Calculate the initial rate of this reaction. (3) Answer
- June 2017, Paper 2, Q9(a)(ii) (2 marks): Explain why adding citric acid to cut fruit reduces the rate at which the fruit turns brown. (2)
- June 2017, Paper 2, Q9(a)(iii) (2 marks): The diagram shows the structures of monophenol and a molecule called tropolone. Tropolone can be added to grape juice to slow the rate at which the juice turns
- June 2017, Paper 2, Q9(b)(ii) (3 marks): The base sequence of this polyphenol oxidase gene is different in this grape variety. Explain how this leads to the production of inactive enzyme. (3)
- June 2017, Paper 3, Q5(a) (1 mark): Name the type of inhibition produced by fluoride ions. (1)
- June 2016, AS Paper 1, Q9(a) (3 marks): Explain the role of the active site in the conversion of succinate to fumarate. (3)
- June 2016, AS Paper 1, Q9(b)(i) (2 marks): Explain why malonate inhibits the activity of succinate dehydrogenase. (2)
- June 2016, AS Paper 1, Q9(b)(ii) (1 mark): On the diagram, draw malonate binding to succinate dehydrogenase. (1)
- June 2016, AS Paper 1, Q9(b)(iii) (1 mark): Which of the following graphs represents the effect of this type of inhibitor? (1) no inhibitor with inhibitor with inhibitor A B no inhibitor Substrate concent
- June 2016, AS Paper 1, Q9(c) (6 marks): The rate of reaction of succinate dehydrogenase can be measured using a methylene blue solution. Methylene blue starts off blue but changes to colourless as suc
Questions, mark schemes and examiner’s reports are © Pearson Edexcel, from their published past papers. Plumi isn’t affiliated with any exam board. Want whole papers? Every Edexcel A-Level Biology B paper.
Rather write your answers by hand on iPad? Plumi marks them against the same mark schemes.