Water and its importance in plants and animals: OCR A‑Level Biology B questions

Every OCR A-Level Biology B exam question on 2.1.2 Water and its importance in plants and animals, 2016–2025, with its mark scheme and examiner’s report.

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Q1(c)
June 2025 · Paper 3
4 marks2.1.2 Water and its importance in plants and animals
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Q18
June 2025 · AS Paper 1
1 mark2.1.2 Water and its importance in plants and animals
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Q2(a)(i)
June 2025 · AS Paper 2
2 marks2.1.2 Water and its importance in plants and animals
No published mark scheme
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Q2(a)(ii)
June 2025 · AS Paper 2
1 mark2.1.2 Water and its importance in plants and animals
No published mark scheme
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Q2(b)(i)
June 2025 · AS Paper 2
1 mark2.1.2 Water and its importance in plants and animals
No published mark scheme
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Q2(b)(ii)
June 2025 · AS Paper 2
1 mark2.1.2 Water and its importance in plants and animals
No published mark scheme
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Q2(b)(iii)
June 2025 · AS Paper 2
2 marks2.1.2 Water and its importance in plants and animals
No published mark scheme
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Q2(b)(iv)
June 2025 · AS Paper 2
4 marks2.1.2 Water and its importance in plants and animals
No published mark scheme
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Q2(c)
June 2025 · AS Paper 2
1 mark2.1.2 Water and its importance in plants and animals
No published mark scheme
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Q1
June 2024 · Paper 1
1 mark2.1.2 Water and its importance in plants and animals
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Q31(b)(iii)
June 2024 · Paper 1
3 marks2.1.2 Water and its importance in plants and animals
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Q3(a)
June 2024 · Paper 2
4 marks2.1.2 Water and its importance in plants and animals
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Q3(b)(i)
June 2024 · Paper 2
3 marks2.1.2 Water and its importance in plants and animals
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Q3(b)(ii)
June 2024 · Paper 2
1 mark2.1.2 Water and its importance in plants and animals
The whole paper ↗
Q3(c)(i)
June 2024 · Paper 2
2 marks2.1.2 Water and its importance in plants and animals
The whole paper ↗
Q3(c)(ii)
June 2024 · Paper 2
1 mark2.1.2 Water and its importance in plants and animals
The whole paper ↗
Q3(c)(iii)
June 2024 · Paper 2
2 marks2.1.2 Water and its importance in plants and animals
The whole paper ↗
Q3(c)(iv)
June 2024 · Paper 2
1 mark2.1.2 Water and its importance in plants and animals
The whole paper ↗
Q1
June 2024 · AS Paper 1
1 mark2.1.2 Water and its importance in plants and animals
The whole paper ↗
Q2
June 2024 · AS Paper 1
1 mark2.1.2 Water and its importance in plants and animals
The whole paper ↗

All 117 questions on Water and its importance in plants and animals, as a list

June 2025, Paper 3, Q1(c) (4 marks): The roots of plants can store starch in high concentrations. Outline how the starch concentration of a sample of root tissue could be estimated using colorimetr
June 2025, AS Paper 1, Q18 (1 mark): As part of a practical activity about osmosis, two students used different apparatus to measure the volume of solution remaining in the Visking tubing at the en
June 2025, AS Paper 2, Q2(a)(i) (2 marks): Draw a molecule of lactose using the galactose molecule above. [2]
June 2025, AS Paper 2, Q2(a)(ii) (1 mark): During digestion lactose is broken down into monosaccharides. Name the reaction involved in digestion. [1]
June 2025, AS Paper 2, Q2(b)(i) (1 mark): Suggest a source of random error in the method. [1]
June 2025, AS Paper 2, Q2(b)(ii) (1 mark): Explain how the method can be modified to reduce the effect of random error. [1] 8 The table shows the data from the investigation. Volume of milk at Volume of
June 2025, AS Paper 2, Q2(b)(iii) (2 marks): Calculate the percentage change in volume for condensed milk. Percentage change = [2]
June 2025, AS Paper 2, Q2(b)(iv) (4 marks): Plot these data using an appropriate format on the grid below. [4]
June 2025, AS Paper 2, Q2(c) (1 mark): Soya milk does not contain lactose. Suggest why the soya milk increased in volume. [1]
June 2024, Paper 1, Q1 (1 mark): The diagram shows a molecule of α-glucose. X O H H H OH H Y OH Z OH The table below shows chemical groups X, Y and Z labelled on the diagram. Chemical group X Y
June 2024, Paper 1, Q31(b)(iii) (3 marks): The students concluded that ‘mock’ urine sample Y represented the urine of a patient with untreated diabetes. One of the students suggested that a colorimeter c
June 2024, Paper 2, Q3(a) (4 marks): Water has some unique properties that make it particularly important as a biological molecule. The table lists some properties of water. Complete the table to d
June 2024, Paper 2, Q3(b)(i) (3 marks): Explain why the different fluids have different total concentrations of solutes and electrolytes. [3]
June 2024, Paper 2, Q3(b)(ii) (1 mark): Based on the values in the table, state and explain the direction you would expect water to move between the tissue fluid and cytosol. [1]
June 2024, Paper 2, Q3(c)(i) (2 marks): Explain one variable that should be controlled in an experiment to measure the osmotic pressure of different solutions. [2]
June 2024, Paper 2, Q3(c)(ii) (1 mark): Describe one improvement to the method to increase the accuracy of the individual measurements. [1]
June 2024, Paper 2, Q3(c)(iii) (2 marks): A student plans to use Pfeffer’s method to study the formation of tissue fluid. A textbook gave the osmotic pressure of blood as 780 kPa at 25 °C. The relations
June 2024, Paper 2, Q3(c)(iv) (1 mark): The student also plans to use a sodium chloride solution with the same osmotic pressure as blood. The van’t Hoff factor takes account of the number of particles
June 2024, AS Paper 1, Q1 (1 mark): Which statement about the fatty acids found in lipids is correct? A They contain only carbon and hydrogen atoms. B One fatty acid joins with three glycerol mole
June 2024, AS Paper 1, Q2 (1 mark): A group of students were testing plant extracts for biological molecules. The table shows the colour of each solution before and after testing the extracts. Col
June 2024, AS Paper 1, Q3 (1 mark): Which statement about water is not correct? A A large amount of heat energy is required to change the temperature of water. B The forces of attraction between w
June 2024, AS Paper 1, Q4 (1 mark): A person weighing 75 kg contains 45 dm3 of body fluid. 4 Approximately 70% of this body fluid is contained within cells as intracellular fluid. Researchers inve
June 2023, Paper 1, Q1 (1 mark): The image shows an erythrocyte after being placed in a solution. Which option explains the appearance of the erythrocyte? A The solution was distilled water. B
June 2023, Paper 3, Q2(b)(iii) (2 marks): The student performed the Benedict’s test on solutions from the leaves of both species. • For each of the species, the same method was used to prepare the solut
June 2023, Paper 3, Q2(b)(iv) (1 mark): The student also tested for the presence of starch in various tissues of the plants. State how to test for starch. [1]
June 2022, Paper 1, Q6 (1 mark): The structure of a polymer is shown below. O HOCH2 H H HO CH2OH OH H O O CH2 H H HO CH2OH OH H O CH2OH 29 repeating units O O CH2 H H H H O OH H H HO HO CH2OH H
June 2022, Paper 1, Q7 (1 mark): Water forms pleural fluid, a lubricant that reduces the friction between the lungs and the thoracic cavity during ventilation. Which of the statements about the
June 2022, Paper 1, Q8 (1 mark): A scientist used a colorimeter during an investigation to measure the concentration of glucose in samples of urine. Which of the statements is/are correct? 1 Th
June 2022, Paper 2, Q1(a) (3 marks): The table shows several conversions that occur in carbohydrate metabolism. Place one tick (3) in the appropriate box in each row to indicate the type of reactio
June 2022, Paper 3, Q1(c) (1 mark): An incomplete structure of α-glucose is shown in Fig. 1.2. CH2OH C O H H C C OH C C H OH Fig. 1.2 Complete the structure of α-glucose in Fig. 1.2 to show all of
June 2022, Paper 3, Q1(d) (2 marks): The table lists glucose and two other carbohydrate molecules: lactose and amylose. Fill in the table to show, for each carbohydrate, a reagent that would give a
June 2022, Paper 3, Q5(a)(i) (3 marks): Suggest and explain three changes that the student could make to the experimental set-up that would increase the rate of osmosis. Change Explanation Change Expl
June 2022, Paper 3, Q5(a)(ii) (1 mark): The student decided to measure the rate of osmosis by measuring how the height of the solution changed over time in the thistle funnel. Suggest appropriate unit
June 2022, Paper 3, Q5(a)(iii) (1 mark): Suggest a semipermeable material that the student could use instead of the goat bladder. [1]
June 2022, AS Paper 1, Q21(b)(i) (1 mark): Name the reagent in the qualitative test that could have been used by the researchers to confirm the presence of starch. [1]
June 2022, AS Paper 1, Q21(b)(ii) (1 mark): Give one reason why the researchers chose a red filter when using colorimetry in this investigation. [1]
June 2022, AS Paper 1, Q21(b)(iii) (3 marks): To determine the concentration of starch in each sample from the colorimetry readings, the researchers needed a calibration curve. Outline how a calibration cur
June 2022, AS Paper 1, Q21(c) (4 marks): Some of the data from this investigation are shown in Fig. 21.1 and Fig. 21.2. 4000 3500 Starch 3000 concentration 2500 in sugarcane 2000 extract (mg dm–3) 1500
June 2022, AS Paper 1, Q21(d)(i) (1 mark): Name the type of reaction catalysed by these enzymes. [1]
June 2022, AS Paper 1, Q21(d)(ii) (1 mark): Name one possible product of the reaction catalysed by α-amylase. [1]
June 2022, AS Paper 1, Q21(d)(iii) (1 mark): Suggest why pullulanase is used to increase the solubility of starch suspensions. [1]
November 2021, Paper 1, Q2 (1 mark): Which of the biofluids, A to D, is not an extracellular fluid? A cell sap B lymph C plasma D urine Your answer [1]
November 2021, Paper 2, Q6(a)(iii) (2 marks): Describe how you could extend this experiment to test the student’s hypothesis. [2]
November 2021, AS Paper 1, Q20 (1 mark): Glutathione (GSH) is a small polymer found in most cells in the human body. The structure of glutathione is shown below. O O H H H H H O O C C C C C N C C N C C
November 2021, AS Paper 1, Q22(a)(i) (2 marks): Identify two precautions that must be taken when using the apparatus in Fig. 22.1 to obtain valid data. 1.. 2.. [2]
November 2021, AS Paper 1, Q22(a)(ii) (2 marks): For one of the precautions you identified in (a)(i) explain why it must be taken to ensure valid data. [2]
November 2021, AS Paper 1, Q22(b)(i) (3 marks): Using your knowledge of osmosis, explain the trends shown by the data in Fig. 22.2 [3]
November 2021, AS Paper 1, Q22(b)(ii) (2 marks): The students used data collected to calculate the rate of pressure change for each concentration of sucrose. They recorded their results in Table 22. Rate of pr
November 2021, AS Paper 1, Q22(b)(iii) (3 marks): Using the grid below, draw a suitable graph to show the results recorded in Table 22. [3]
November 2021, AS Paper 1, Q22(b)(iv) (1 mark): Use your graph in (b)(iii) to estimate the concentration of sucrose solution for which the rate of pressure change was zero. Concentration = mol dm 3 [1]
November 2021, AS Paper 2, Q1(c) (2 marks): Saline is salt solution. Using your knowledge of osmosis, explain how breathing in a fine mist of saline could reduce oxygen consumption. [2]
November 2021, AS Paper 2, Q5(a) (3 marks): State three improvements that the scientist could make to the method. 1 2 3 [3]
November 2021, AS Paper 2, Q5(b) (1 mark): Suggest a suitable control for the investigation. [1]
November 2021, AS Paper 2, Q5(c) (1 mark): The results of the investigation are shown in the graph. 1.2 1.0 0.8 mass of precipitate 0.6 (g) 0.4 0.2 0 0 1 2 3 4 5 6 concentration of reducing sugar (%) The
November 2021, AS Paper 2, Q5(d) (4 marks): The concentration of sugar in the energy drink was 5.5% as it also contained non-reducing sugars. State two additional steps that could be added to the method t
November 2020, Paper 1, Q29 (1 mark): Water flows continuously through xylem vessels due to cohesion. Which of the options, A to D, is responsible for the cohesive properties of water? A covalent bo
November 2020, Paper 1, Q33(a)(i) (2 marks): Outline a test that could be used to detect glucose in a urine sample. [2]
November 2020, Paper 1, Q33(a)(ii) (2 marks): Draw the ring structure of a molecule of glucose in the space below. [2]
November 2020, Paper 1, Q34(d)(i) (1 mark): Name a technique that can determine the concentration of a known molecule in a solution by measuring light absorbance. [1]
November 2020, AS Paper 1, Q17 (1 mark): α-glucose is an example of a monosaccharide sugar. Which of the options, A to D, is not a property of monosaccharides? A general formula CnH2nOn B soluble in wa
November 2020, AS Paper 2, Q3(a)(i) (2 marks): Calculate the percentage increase in the distance moved by the meniscus between 0.4 mol dm–3 and 0.6 mol dm–3 sodium chloride. percentage increase = % [2]
November 2020, AS Paper 2, Q3(a)(ii) (1 mark): Explain why the Visking tubing containing carrot extract was left for 24 hours in the sodium chloride solution. [1]
November 2020, AS Paper 2, Q3(a)(iii) (2 marks): What conclusions can be made about the movement of water from the results given in the table? [2]
November 2020, AS Paper 2, Q3(a)(iv) (3 marks): Explain how the investigation could be modified to find the concentration of sodium chloride solution that has the same water potential as the carrot extract. [
November 2020, AS Paper 2, Q3(a)(v) (2 marks): Explain how the student could have calculated the initial rate of osmosis in the different concentrations of sodium chloride. [2]
November 2020, AS Paper 2, Q3(b)(i) (2 marks): It is important to use carrots of a similar age when preparing extracts for this investigation. Explain how using carrots of different ages could affect the res
November 2020, AS Paper 2, Q3(b)(ii) (1 mark): Give one reason why using a Benedict’s test to compare the sugar content of carrot extracts may not give valid results. [1]
June 2019, Paper 1, Q2 (1 mark): Which of the options, A to D, is a type of reaction involved in the breakdown of a phospholipid? A condensation B dehydrogenation C hydrolysis D phosphorylation
June 2019, Paper 1, Q33(a)(i) (2 marks): Calculate the standard deviation for the final mass of potato slices soaked in 0.6 mol dm–3 sucrose concentration. 2 - / ( x x ) Use the formula: s = n 1 - stan
June 2019, Paper 1, Q33(a)(ii) (2 marks): The graph below represents the data in Table 33. 2.90 2.80 2.70 2.60 mean final mass 2.50 of potato slice / g 2.40 2.30 2.20 2.10 0.0 0.2 0.4 0.6 0.8 1.0 sucros
June 2019, Paper 1, Q33(a)(iii) (3 marks): With reference to the data in Table 33, explain how the sucrose concentration of the solution determines the final mass of potato. [3]
June 2019, Paper 1, Q33(a)(iv) (2 marks): Suggest two factors in the method that could have contributed error to the data, as shown by the error bars in the graph in (a)(ii) on page 25. 1 2 [2]
June 2019, Paper 3, Q3(a) (1 mark): Give one reason why the student chose method 2. [1]
June 2019, Paper 3, Q3(b) (6 marks): A student was asked to find out the glucose concentration in mock body fluids. The student was provided with three samples. The student’s plan contained the fol
June 2019, Paper 3, Q3(c) (3 marks): A teacher was asked to comment on the method and results collected. Complete the paragraph by choosing the most appropriate word from the list below. anomaly ac
June 2019, AS Paper 1, Q5 (1 mark): Linseed oil is a polyunsaturated triglyceride that can be extracted from the seeds of the flax plant, Linum usitatissimum. A diagram of a linseed oil molecule i
June 2019, AS Paper 2, Q1(a)(i) (1 mark): Using Fig. 1.1, describe one visible similarity between fructose and α-glucose. [1]
June 2019, AS Paper 2, Q1(a)(ii) (1 mark): Using Fig. 1.1, describe one visible difference between fructose and α-glucose. [1]
June 2019, AS Paper 2, Q1(c)(i) (1 mark): Suggest the expected observation for test tube D and give a reason for your answer. [1]
June 2019, AS Paper 2, Q1(c)(ii) (1 mark): Suggest why sodium hydrogencarbonate was added to all four test tubes. [1]
June 2019, AS Paper 2, Q1(c)(iii) (2 marks): The student proposed that: Dilute hydrochloric acid played a significant part in the hydrolysis of potato starch. Describe a suitable control that the student c
June 2019, AS Paper 2, Q1(c)(iv) (1 mark): The students found it difficult to compare each other’s observations on the colour changes. What method could they have used to obtain quantitative results? [1]
June 2018, Paper 1, Q36(a) (3 marks): Draw a second water molecule on Fig. 36.1, in the position it might take up beside the first water molecule. Your drawing should show: • the bond(s) between the
June 2018, Paper 1, Q36(b)(i) (1 mark): State the precise name of the chemical bond in starch that is hydrolysed by amylase. [1]
June 2018, Paper 1, Q36(b)(ii) (1 mark): Reagent X was used to indicate the presence or absence of starch in the agar plates. State the name of this reagent and its colour in the presence of starch. Na
June 2018, Paper 3, Q2(a)(i) (1 mark): All equipment and sections of carrot were washed with distilled water before use. Explain why. [1]
June 2018, Paper 3, Q2(a)(ii) (1 mark): The absorbance value obtained in step 4 was used as a reference value for further tests. This absorbance value was considered to represent the highest chloride
June 2018, Paper 3, Q2(b) (1 mark): Look at the trend in the results in Table 2.1. Identify the anomalous result in this trend and give its expected absorbance value. Anomalous result Expected abs
June 2018, Paper 3, Q2(c) (6 marks): The student used the method for the preliminary experiment to plan their investigation into the effect of temperature on the rate of chloride ion diffusion. Des
June 2018, Paper 3, Q2(d)(i) (1 mark): Use Fig. 2.1 to calculate the increase in absorbance between 10 °C and 40 °C. Answer = [1]
June 2018, Paper 3, Q2(d)(ii) (2 marks): Suggest why the absorbance changed between 10 °C and 40 °C. [2] 11 Fig. 2.2 shows absorbance measured at different concentrations of chloride ions. 1 0.1 absorb
June 2018, Paper 3, Q2(d)(iii) (2 marks): Using the graph in Fig. 2.1 and the graph in Fig. 2.2, estimate the chloride ion concentration at a temperature of 45 °C. [2]
June 2018, AS Paper 1, Q1 (1 mark): Which of the options, A to D, is an intracellular biofluid? A blood plasma B cytoplasm C tissue fluid D serum Your answer [1]
June 2018, AS Paper 1, Q2 (1 mark): A plant cell with a water potential of −500 KPa was placed in a solution which caused the cell membrane to completely pull away from the cell wall. Which of the
June 2018, AS Paper 1, Q23(a) (4 marks): The table below shows some of the properties of water and their importance to living organisms. Complete the table using the most appropriate term(s) or sentenc
June 2018, AS Paper 1, Q23(b)(i) (1 mark): Name the types of reaction taking place at X and Y. Reaction X Reaction Y [1]
June 2018, AS Paper 1, Q23(b)(ii) (1 mark): Name both products of reaction X. [1]
June 2018, AS Paper 1, Q23(b)(iii) (1 mark): Name the bond labelled Z. [1]
June 2018, AS Paper 2, Q5(a) (2 marks): Using the information in Fig. 5, draw a diagram of a sucrose molecule in the space below. [2]
June 2018, AS Paper 2, Q5(d) (3 marks): The presence of starch in seeds can be detected using iodine-KI reagent. When tested with iodine-KI reagent, dry seeds showed a high concentration of starch but
June 2017, Paper 1, Q13 (1 mark): Three diagnostic tests were performed on a solution containing a biological molecule. The results of the tests are shown in the table below. Colour of test reag
June 2017, Paper 2, Q6(b)(i) (1 mark): Explain why the term ‘plasmolysis’ is used incorrectly in this student’s description. [1]
June 2017, Paper 2, Q6(b)(ii) (2 marks): State two ways in which the experimental procedure described by the student could be improved. improvement 1 improvement 2 [2]
June 2017, AS Paper 1, Q19 (1 mark): Which of the molecules, A to D, can be described as a pentose monosaccharide with a general formula of Cx(H2O)y ? CH2OH O CH2OH H O H H H HO CH2OH OH H H HO OH
June 2017, AS Paper 2, Q6(a)(i) (1 mark): What is the purpose of the differential stain in this investigation? [1]
June 2017, AS Paper 2, Q6(a)(ii) (1 mark): The student made the following statement: ‘The water potential of the onion cells changes when the cells are stained with the differential stain.’ Is this state
June 2017, AS Paper 2, Q6(a)(iii) (4 marks): Identify two sources of error in the procedure used and suggest an improvement for each. error improvement error improvement [4]
June 2017, AS Paper 2, Q6(b)(i) (3 marks): Using the data in Table 6, complete an appropriate graph on the grid provided. 70 60 50 40 30 20 10 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 [3]
June 2017, AS Paper 2, Q6(b)(ii) (1 mark): Using your graph plotted in (b)(i), state the sucrose concentration at which 50% of the onion cells are plasmolysed. [1]
June 2016, AS Paper 1, Q8 (1 mark): Lactose is formed by a reaction between glucose and galactose, both of which have the chemical formula C6H12O6. Which of the options, A to D, is the correct che
June 2016, AS Paper 1, Q10 (1 mark): A student wrote the following statement: ‘Water is polar because the oxygen side of the molecule is slightly positive in charge.’ Which of the following options
June 2016, AS Paper 1, Q21(a) (2 marks): Using Fig. 21, explain the results for the suspension in test tube B. [2]
June 2016, AS Paper 1, Q21(b) (1 mark): The students waited for 15 minutes after adding the erythrocyte suspensions to the sodium chloride solutions before recording their observations. Explain why. [
June 2016, AS Paper 1, Q21(c) (3 marks): The students repeated the experiment using a colorimeter to measure the absorbance of each erythrocyte suspension after 15 minutes. Table 21.1 below shows the d
June 2016, AS Paper 1, Q21(d)(i) (2 marks): Compare the results for concentrations of glucose and sodium chloride between 0.05 and 0.20 mol dm–3. [2]
June 2016, AS Paper 1, Q21(d)(ii) (1 mark): The students forgot to take the measurement for absorbance at 0.25 mol dm–3 glucose concentration. Suggest how the missing data could affect the conclusions mad
June 2016, AS Paper 2, Q2(a) (2 marks): Describe a method the students could use to confirm the presence of protein in the sports drink. [2]

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