Practical skills: Edexcel International A Level Biology questions

Every Edexcel International A Level Biology exam question on Practical skills, 2019–2025, with its mark scheme and examiner’s report.

All 391 questions on Practical skills, as a list

June 2025, AS Unit 3, Q1(b)(i) (2 marks): Explain why a temperature of 25 °C was used. (2)
June 2025, AS Unit 3, Q1(b)(ii) (1 mark): State the independent variable in this investigation. (1)
June 2025, AS Unit 3, Q1(b)(iii) (2 marks): Give two reasons why the grains were germinated before being transferred to the Petri dishes. (2) 1 2
June 2025, AS Unit 3, Q1(b)(iv) (2 marks): Explain why some seedlings were placed in the solvent without trifluralin. (2)
June 2025, AS Unit 3, Q1(c)(i) (4 marks): Describe how a root sample could have been prepared and examined to obtain these results. (4)
June 2025, AS Unit 3, Q2(a)(i) (5 marks): Justify each step of a method that could be used to obtain the results shown in the graph. (5)
June 2025, AS Unit 3, Q2(a)(ii) (3 marks): Draw a table that includes only the results obtained at 20 hours. (3)
June 2025, AS Unit 3, Q2(a)(iii) (4 marks): Plot a suitable graph for the results obtained at 20 hours. (4)
June 2025, AS Unit 3, Q3(a)(ii) (3 marks): Explain how colour standards can be used as a semi‑quantitative method of estimating the concentration of starch in a sample. (3)
June 2025, AS Unit 3, Q3(a)(iii) (2 marks): Describe the difference between a result obtained from a quantitative test and a result obtained from a semi‑quantitative test. (2)
June 2025, AS Unit 3, Q3(b)(i) (2 marks): Calculate the percentage difference between the highest and lowest values obtained from these nine regions. Use the formula: difference between two values
June 2025, AS Unit 3, Q3(b)(ii) (3 marks): Describe how to determine the total mass of starch present in section B of this root. (3)
June 2025, AS Unit 3, Q3(b)(iii) (3 marks): Describe how this investigation could be extended to determine the variability in the concentration of starch in different cassava roots. (3)
June 2025, Unit 6, Q1(b) (6 marks): Describe an experiment to investigate the rate of respiration of yeast cells at different temperatures, using an artificial hydrogen carrier. (6)
June 2025, Unit 6, Q2(b)(i) (2 marks): Describe a method to select at random the five sample sites. (2)
June 2025, Unit 6, Q2(b)(ii) (2 marks): The tables show the results of this investigation. 5‑year‑old plantation Sample site Mass of earthworms / g 1 12.3 2 14.7 3 15.2 4 10.8 5 11.1 mean 12.8 SD 2.0
June 2025, Unit 6, Q2(b)(iii) (2 marks): Describe how the means and standard deviations could be used to compare the results from these two plantations. (2)
June 2025, Unit 6, Q2(c)(i) (2 marks): State two abiotic variables, other than temperature, that could affect this investigation. (2) first variable second variable
June 2025, Unit 6, Q2(c)(ii) (1 mark): Choose one of the variables you have identified in part (c)(i). Describe how this variable can be controlled. (1) Variable Method of control
June 2025, Unit 6, Q3(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
June 2025, Unit 6, Q3(b) (3 marks): The table shows the results of this investigation. Time from beginning of Mean percentage of crude oil investigation / days left in the soil trays (%) 0 1.50 30
June 2025, Unit 6, Q3(c)(i) (2 marks): Calculate the correlation coefficient, rs, using the formula: 6 d 2 r 1 s n n 1 2 Where: d = the difference between each pair of ranks n = the size of the sam
June 2025, Unit 6, Q3(c)(ii) (2 marks): The table shows some critical values for this statistical test. Number Level of significance (p) of pairs of values (n) 0.10 0.05 0.01 4 1.000 – – 5 0.900 1.000
June 2025, Unit 6, Q3(d) (6 marks): Bacteria in the desert soil can break down crude oil. A scientist predicted that the number of bacteria in the desert soil would increase as the crude oil was b
June 2025, Unit 6, Q4(a) (2 marks): Describe one ethical concern and one safety precaution the student must consider before practical work can begin. (2) Ethical concern Safety precaution
June 2025, Unit 6, Q4(b) (9 marks): Devise a detailed method, including how you would control and monitor important variables to provide quantitative results. (9)
June 2025, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
June 2025, Unit 6, Q4(d) (2 marks): Describe two limitations of your proposed method. (2)
January 2025, AS Unit 3, Q1(b)(ii) (4 marks): Describe how to investigate the relationship between the length of these fibres and their tensile strength. (4)
January 2025, AS Unit 3, Q1(c)(i) (3 marks): Draw a table to show all the results shown in the graph. (3)
January 2025, AS Unit 3, Q1(c)(ii) (1 mark): Calculate the gradient of the line of best fit shown in this graph. (1) Answer
January 2025, AS Unit 3, Q1(c)(iii) (2 marks): Write the equation for the line of best fit shown in this graph. Use the graph and your answer to part (ii) to write this equation. (2) Equation for this line o
January 2025, AS Unit 3, Q2(b)(i) (4 marks): Plot a graph to show all the data. (4)
January 2025, AS Unit 3, Q2(b)(ii) (6 marks): Describe how the data in the table could be obtained. (6)
January 2025, AS Unit 3, Q3(c)(i) (1 mark): State the independent variable in this study. (1)
January 2025, Unit 5, Q5(d)(ii) (2 marks): Describe how the investigation was designed so that error bars could be produced. (2)
January 2025, Unit 5, Q5(d)(iii) (1 mark): State how the error bars can be used to interpret the results of this investigation. (1)
January 2025, Unit 6, Q1(a) (6 marks): Describe an experiment to investigate the effect of the concentration of copper ions on the time taken for the brine shrimps to hatch from eggs. (6)
January 2025, Unit 6, Q1(b) (1 mark): Suggest why using brine shrimps in this investigation does not create any ethical concerns. (1)
January 2025, Unit 6, Q2(a) (4 marks): Describe a sampling method that could be used to collect valid data to investigate this observation. (4)
January 2025, Unit 6, Q2(b)(i) (1 mark): Complete the table to show the expected (E) results. (1)
January 2025, Unit 6, Q2(b)(ii) (2 marks): Calculate the value of Chi squared (χ2) using the formula: 2 ( O E ) χ 2 E (2) Answer
January 2025, Unit 6, Q2(b)(iii) (1 mark): Give one reason why the student used a Chi squared test to analyse these data. (1)
January 2025, Unit 6, Q2(b)(iv) (2 marks): State two abiotic variables, other than mineral ions, that could affect the results of this investigation. (2) first variable second variable
January 2025, Unit 6, Q3(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
January 2025, Unit 6, Q3(b) (3 marks): Draw a suitable graph to show the results in this table. (3)
January 2025, Unit 6, Q3(c)(i) (1 mark): Complete the table. (1)
January 2025, Unit 6, Q3(c)(ii) (2 marks): Calculate the correlation coefficient, rs, using the formula: (2) 6 d 2 r 1 s 2 n n 1 Where: ∑ = the sum of d = the difference between each pair of ranks n =
January 2025, Unit 6, Q3(c)(iii) (2 marks): The table shows some critical values for this statistical test. Number Level of significance (p) of pairs of values 0.10 0.05 0.01 4 1.000 – – 5 0.900 1.000 – 6
January 2025, Unit 6, Q3(d) (2 marks): Describe how the student could extend this investigation to collect more data to either support or reject the null hypothesis, in part (a). (2)
January 2025, Unit 6, Q4(a) (2 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (2)
January 2025, Unit 6, Q4(b) (9 marks): Devise a detailed method, including how you would control and monitor important variables. (9)
January 2025, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
January 2025, Unit 6, Q4(d) (2 marks): Suggest two limitations of your proposed method. (2)
October 2024, AS Unit 3, Q1(b)(ii) (3 marks): Studies have shown the effect of temperature on starch synthesis. In an investigation, the rate of starch synthesis was measured at four different temperatures.
October 2024, AS Unit 3, Q1(b)(iii) (2 marks): Explain what the value for the standard deviation at 30°C means in this investigation. (2) Value of standard deviation Explanation
October 2024, AS Unit 3, Q1(b)(iv) (2 marks): Justify conclusions about the changes in mean rate of starch synthesis between 20°C and 25°C and between 25°C and 30°C. (2) 20°C and 25°C 25°C and 30°C
October 2024, AS Unit 3, Q1(c)(ii) (4 marks): Plot a graph of the data in the table and join the points with straight lines. (4)
October 2024, AS Unit 3, Q2(a)(i) (4 marks): Describe a method that could be used to obtain the results for the complete Hoagland treatment, so that it can be compared with the other treatments. (4)
October 2024, AS Unit 3, Q2(b)(i) (2 marks): Suggest why shoot dry mass is a more accurate measure than the length of a fresh shoot. (2)
October 2024, AS Unit 3, Q3(a)(i) (2 marks): Explain why the dishes were incubated for 48 hours at 30°C. (2) 48 hours 30°C
October 2024, AS Unit 3, Q3(b)(i) (2 marks): Explain how the area of the zone of inhibition could be measured accurately. (2)
October 2024, AS Unit 3, Q3(b)(ii) (1 mark): State one independent variable in this investigation. (1)
October 2024, AS Unit 3, Q3(c)(ii) (2 marks): A method that avoids this problem is to find the minimum inhibitory concentration (MIC) of the extract. The MIC can be defined as the minimum concentration of t
October 2024, Unit 6, Q1(b) (6 marks): The drawing shows a wheat grain and the locations of the endosperm and the embryo. endosperm embryo Describe an experiment to determine if gibberellin stimulate
October 2024, Unit 6, Q2(a) (2 marks): Describe how the scientist could reduce one risk when using this apparatus. (2) Risk How the scientist could reduce this risk
October 2024, Unit 6, Q2(b) (3 marks): The table shows the results of this investigation. Force needed to break a fibre treated Force needed to break an untreated fibre with hydrogen peroxide / MPa /
October 2024, Unit 6, Q2(c)(i) (2 marks): State one abiotic and one biotic variable, other than temperature, that could affect this investigation. (2) Abiotic variable Biotic variable
October 2024, Unit 6, Q2(c)(ii) (1 mark): Choose one of the variables you have identified in part (i). State how this variable can be controlled. (1) Variable Method of control
October 2024, Unit 6, Q3(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
October 2024, Unit 6, Q3(b) (3 marks): Draw a suitable table to display the data and your calculated means. (3)
October 2024, Unit 6, Q3(c) (3 marks): Draw a suitable graph to show the mean mitotic index after two days in 20% oxygen and the mean mitotic index after two days in 5% oxygen. Include an indication
October 2024, Unit 6, Q3(d)(i) (2 marks): Calculate the value of t. (2) Answer
October 2024, Unit 6, Q3(d)(ii) (3 marks): The table shows the critical values of t for different degrees of freedom. The number of degrees of freedom = (nA – 1) + (nB – 1) Degrees of freedom p = 0.05 p
October 2024, Unit 6, Q3(e) (2 marks): Describe how the scientist could extend this investigation to collect more data to either support or reject the hypothesis. (2)
October 2024, Unit 6, Q4(a) (2 marks): Describe the preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (2)
October 2024, Unit 6, Q4(b) (9 marks): Devise a detailed method, including how you would control and monitor important variables. (9)
October 2024, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
October 2024, Unit 6, Q4(d) (2 marks): Suggest two limitations of your proposed method. (2)
June 2024, AS Unit 3, Q1(a) (2 marks): Explain why, in step 1, it is important to cut the squid meat into equal sized pieces. (2)
June 2024, AS Unit 3, Q1(b)(i) (1 mark): Name a suitable control solution that could be used in step 2. (1)
June 2024, AS Unit 3, Q1(b)(ii) (1 mark): State the importance of using a control in this study. (1)
June 2024, AS Unit 3, Q1(c) (1 mark): Give two variables that need to be controlled in step 3. (1) 1 2
June 2024, AS Unit 3, Q1(d)(i) (1 mark): The 0.001% enzyme solution was prepared by diluting the 0.004% enzyme solution. Calculate the volume of the 0.004% enzyme solution needed to make 50 cm3 of 0.00
June 2024, AS Unit 3, Q2(a) (1 mark): Calculate the actual length of this fish between X and Y. Give your answer in metres. (1) Answer m
June 2024, AS Unit 3, Q2(b) (4 marks): A student wanted to compare the heart of this fish with the heart of a mammal. The student planned to cut open the fish and remove its heart and to keep the hea
June 2024, AS Unit 3, Q2(d) (6 marks): A student suggested that: The larger a fish is, the larger its heart will be. Devise a method that could be used to collect and analyse data to test this sugges
June 2024, AS Unit 3, Q3(a)(ii) (4 marks): Plot a suitable graph to show the relationship between storage time and the vitamin C content in the fruits coated with cinnamon oil. Draw a line of best fit th
June 2024, AS Unit 3, Q3(a)(iii) (3 marks): This data has no indication of repeatability. Describe how data could have been collected in this investigation and presented to show its repeatability. (3)
June 2024, AS Unit 3, Q3(a)(iv) (3 marks): A coating made from a combination of chitosan and cinnamon oil was also tested. Describe an investigation to determine if this coating is more effective than th
June 2024, AS Unit 3, Q3(b)(i) (2 marks): The diagram shows a graduated pipette. The pipette was used to prepare the suspension of bacteria. Describe how to use a graduated pipette to measure an accurat
June 2024, AS Unit 3, Q3(b)(ii) (1 mark): The suspension of bacteria containing 5 × 105 bacteria per cm3 was used. Each agar plate was spread with 0.2 cm3 of this suspension. Calculate the number of bac
June 2024, AS Unit 3, Q3(b)(iii) (2 marks): Explain two safety precautions that must be taken when preparing these plates. (2) 1 2
June 2024, AS Unit 3, Q3(b)(iv) (3 marks): The table shows some differences between the method using bacteria and the method using fungi. Type of Incubation Length of Type of agar microorganism temperatu
June 2024, Unit 6, Q1(b) (5 marks): Describe an experiment to investigate the effect of temperature on the rate of respiration in yeast, using an artificial hydrogen carrier (redox indicator). (5)
June 2024, Unit 6, Q2(a) (4 marks): Woodlice are small animals that live in damp places, for example under stones and in areas with decomposing leaves. The photograph shows one species of woodlous
June 2024, Unit 6, Q2(b)(ii) (3 marks): Plot a line graph for the results of this investigation. (3)
June 2024, Unit 6, Q2(b)(iii) (1 mark): Give one way that this investigation should be conducted to avoid harming the fish. (1)
June 2024, Unit 6, Q2(b)(iv) (2 marks): State one abiotic and one biotic variable that could affect this investigation of habituation in zebrafish. (2) Abiotic variable Biotic variable
June 2024, Unit 6, Q2(b)(v) (2 marks): Choose one of the variables you have identified in (iv). Describe how this variable could be controlled and the effect it would have on the results if it is not
June 2024, Unit 6, Q3(b)(i) (3 marks): Calculate the Chi-squared value using the formula: (3) ( O E ) 2 χ 2 E Answer
June 2024, Unit 6, Q3(b)(ii) (3 marks): The table shows some critical values for Chi-squared at different degrees of freedom. Degrees of p value = 0.050 freedom 1 3.841 2 5.991 3 7.815 4 9.488 Comment
June 2024, Unit 6, Q3(b)(iii) (3 marks): Justify three improvements that could be made to this investigation. (3)
June 2024, Unit 6, Q4(a) (3 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (3)
June 2024, Unit 6, Q4(b) (8 marks): Devise a detailed method, including how you would control and monitor important variables. (8)
June 2024, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
June 2024, Unit 6, Q4(d) (3 marks): Suggest three limitations of your proposed method. (3)
January 2024, AS Unit 3, Q1(b) (5 marks): The vitamin C content of the leaves from spinach plants was investigated. Describe how comparative measurements of the vitamin C content of the leaves from two
January 2024, AS Unit 3, Q1(c)(i) (3 marks): The table shows the data required to calculate the missing standard deviation for the spinach grown in soil type 2 in the autumn. (x – x )2 0.031 0.009 0.031 0.
January 2024, AS Unit 3, Q1(c)(ii) (3 marks): The graph shows the means from this investigation. Complete this graph by adding the axes, values and labels, together with the standard deviations. (3)
January 2024, AS Unit 3, Q2(c)(ii) (5 marks): Describe a procedure that could have been used to obtain the results shown in this graph. (5)
January 2024, AS Unit 3, Q3(a)(iv) (2 marks): Suggest how this investigation could be adapted to increase the accuracy of the estimate. (2)
January 2024, AS Unit 3, Q3(b)(i) (3 marks): Draw a table to display all the results shown in this graph. (3)
January 2024, AS Unit 3, Q3(b)(ii) (3 marks): Calculate the gradient of the line at 7 days. Include units in your answer. (3) Answer
January 2024, AS Unit 3, Q3(b)(iv) (6 marks): This process preserves the animal feed because it kills bacteria. The process involves heating for a period of time, the heating temperature and the addition of
January 2024, Unit 6, Q1(a) (6 marks): Describe how the antibacterial activity of different parts of this plant could be compared. (6)
January 2024, Unit 6, Q2(a) (2 marks): Calculate the mean rate of growth of the pollen tubes between one and five hours. Include units with your answer. (2) Answer
January 2024, Unit 6, Q2(c)(i) (2 marks): State two abiotic variables other than temperature that could affect this investigation. (2) First variable Second variable
January 2024, Unit 6, Q2(c)(ii) (1 mark): Choose one of the variables you have identified in (i). Describe how this variable can be controlled. (1) Variable Method of control
January 2024, Unit 6, Q2(c)(iii) (1 mark): Suggest what effect not controlling this variable would have on the results. (1)
January 2024, Unit 6, Q2(d) (2 marks): Describe how this method can be modified to investigate the effect of age of pollen on the rate of growth of pollen tubes. (2)
January 2024, Unit 6, Q3(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
January 2024, Unit 6, Q3(b) (3 marks): Draw a suitable table to display the data and your calculated means for the toepad area of sample A and the toepad area of sample B. (3)
January 2024, Unit 6, Q3(c) (3 marks): Draw a suitable graph to show the mean toepad area for sample A and for sample B. Include an indication of the variability of the data. (3)
January 2024, Unit 6, Q3(d)(i) (3 marks): Calculate the value of t. (3) Answer
January 2024, Unit 6, Q3(d)(ii) (2 marks): The table shows the critical values of t for different degrees of freedom. The number of degrees of freedom = (nA – 1) + (nB – 1) Degrees of freedom p = 0.05 8
January 2024, Unit 6, Q3(e) (2 marks): Describe how the scientist could extend this investigation to collect more data to either support or reject the hypothesis. (2)
January 2024, Unit 6, Q4(a) (2 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. . (2)
January 2024, Unit 6, Q4(b) (9 marks): Devise a detailed method, including how you would control and monitor important variables. (9)
January 2024, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
January 2024, Unit 6, Q4(d) (2 marks): Suggest two limitations of your proposed method. (2)
October 2023, AS Unit 3, Q1(a)(i) (5 marks): Describe a procedure for the accurate determination of the diameter of cell A. (5)
October 2023, AS Unit 3, Q2(a)(ii) (2 marks): Complete the table of results from tests on standard glucose solutions. (2) Glucose concentration Appearance Glucose quantity / g dm–3 Blue 0.0 None Green with
October 2023, AS Unit 3, Q2(b)(i) (2 marks): Describe how the measurements for blood glucose concentration taken in this study were processed to give the data in the table. (2)
October 2023, AS Unit 3, Q2(b)(ii) (5 marks): Plot a suitable graph to show the relationship between mean urine glucose concentration and mean blood glucose concentration. Plot the standard deviation for th
October 2023, AS Unit 3, Q2(b)(iii) (3 marks): Comment on the conclusion that urine glucose concentration is a good indicator of the blood glucose level. Use the information in the table and in your graph to
October 2023, AS Unit 3, Q2(b)(iv) (3 marks): Calculate the blood glucose concentration at a urine glucose concentration of 12 a.u. The equation for the line of best fit is y = 29.3x + 154.1. Give your answ
October 2023, AS Unit 3, Q3(b)(i) (1 mark): State the independent variable in this investigation. (1)
October 2023, AS Unit 3, Q3(b)(ii) (5 marks): Describe a suitable and safe procedure to obtain all the data shown in the graph. (5)
October 2023, AS Unit 3, Q3(b)(iii) (3 marks): Draw a table to show these results. (3)
October 2023, AS Unit 3, Q3(b)(vi) (2 marks): Justify the selection of a named statistical test to be performed on these data. (2) Statistical test Reason
October 2023, Unit 6, Q1(a) (1 mark): A student found the vitamin C content of camu camu fruits changed with the length of time in storage. Freshly picked fruits had a mean vitamin C content of 2 40
October 2023, Unit 6, Q1(b) (6 marks): The student read that ‘the vitamin C content of these fruits decreases the most during the first 14 days of storage.’ Describe an experiment to investigate the
October 2023, Unit 6, Q2(a) (2 marks): Suggest one risk the volunteer subjects might encounter when using this spirometer and how the student could reduce the risk. (2) Risk How the student could red
October 2023, Unit 6, Q2(c)(i) (2 marks): State two biotic variables that could affect this investigation. (2) First variable Second variable
October 2023, Unit 6, Q2(c)(ii) (1 mark): Choose one of the variables you have identified in (i). Describe how this variable can be controlled. (1) Variable Method of control
October 2023, Unit 6, Q3(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
October 2023, Unit 6, Q3(b) (3 marks): Draw a suitable table to display the data and your calculated means for the mass of leaves eaten for these varieties of sorghum. (3)
October 2023, Unit 6, Q3(c) (3 marks): Draw a suitable graph to show the mean mass of leaves eaten of variety A and variety B. Include an indication of the variability of the data. (3)
October 2023, Unit 6, Q3(d)(i) (2 marks): Calculate the value of t. (2) Answer
October 2023, Unit 6, Q3(d)(ii) (2 marks): The table shows the critical values of t for different degrees of freedom. The number of degrees of freedom = (n1 – 1) + (n2 – 1). Degrees of freedom p = 0.05 p
October 2023, Unit 6, Q3(e) (2 marks): Describe how the student could extend this investigation to collect more data to either support or reject the hypothesis. (2)
October 2023, Unit 6, Q4(a) (2 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (2)
October 2023, Unit 6, Q4(b) (9 marks): Devise a detailed method, including how you would control and monitor important variables. (9)
October 2023, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
October 2023, Unit 6, Q4(d) (2 marks): Suggest two limitations of your proposed method. (2)
June 2023, AS Unit 3, Q1(b)(i) (1 mark): Name the independent variable in this investigation. (1)
June 2023, AS Unit 3, Q1(b)(ii) (3 marks): After soaking, the diameter of each fibre was measured. Describe how fibre diameter could be measured accurately using a microscope. (3)
June 2023, AS Unit 3, Q1(b)(iii) (2 marks): Give two reasons why fibre diameter was measured. (2) 1 2
June 2023, AS Unit 3, Q1(c)(i) (4 marks): Plot a suitable graph to show the effect of soaking time on tensile strength. Join the points with straight lines. (4)
June 2023, AS Unit 3, Q2(b) (5 marks): The percentage germination of the pollen grains was used to determine the viability of the pollen. Describe a procedure to compare the percentage germination of
June 2023, AS Unit 3, Q2(c)(ii) (4 marks): Describe how the investigation could be modified to allow the significance of the difference between the percentage germination for bee collected pollen and han
June 2023, AS Unit 3, Q3(a)(ii) (4 marks): Describe a method to obtain the data in this graph. (4)
June 2023, AS Unit 3, Q3(b) (3 marks): Draw a table to show the data in the graph. (3)
June 2023, Unit 6, Q1(b)(i) (6 marks): Describe an experiment to measure the mitotic index of cells from onion roots treated with different concentrations of caffeine solution. (6)
June 2023, Unit 6, Q2(b) (2 marks): Suggest one risk the scientist might encounter when carrying out this investigation and how you could reduce this risk. (2) Risk How to reduce the risk
June 2023, Unit 6, Q2(c)(i) (3 marks): An odds ratio can be used to determine if the presence of mimosa trees has an effect on the presence of the cactus plants. Calculate an odds ratio using the fol
June 2023, Unit 6, Q2(c)(ii) (1 mark): The table shows how the odds ratio can be used in this investigation. Odds ratio Presence of mimosa trees Reduces the likelihood of cactus plants being present
June 2023, Unit 6, Q2(d)(i) (2 marks): State two abiotic variables in the soil that could affect this investigation. (2) First variable Second variable
June 2023, Unit 6, Q2(d)(ii) (1 mark): Choose one of the variables you have identified in (i). State the effect it could have on the results if the measured values were not similar. (1) Variable The
June 2023, Unit 6, Q3(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
June 2023, Unit 6, Q3(b) (2 marks): Draw a suitable table to display these data and the calculated means for the number of pupae from the flasks containing the untreated and treated culture medium
June 2023, Unit 6, Q3(c) (3 marks): Draw a suitable graph to show the mean number of pupae from the untreated culture medium and treated culture medium. Include an indication of the variability of
June 2023, Unit 6, Q3(d)(i) (2 marks): Calculate the value of t. (2) Answer
June 2023, Unit 6, Q3(d)(ii) (2 marks): The table shows the critical values of t for different degrees of freedom. The number of degrees of freedom = (nA – 1) + (nB – 1) Degrees of freedom p = 0.05 p
June 2023, Unit 6, Q3(e) (2 marks): Describe two ways this investigation could be extended to collect more data to either support or reject the hypothesis. (2)
June 2023, Unit 6, Q4(a) (2 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (2)
June 2023, Unit 6, Q4(b) (9 marks): Devise a detailed method, including how you would control and monitor important variables. (9)
June 2023, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
June 2023, Unit 6, Q4(d) (2 marks): Describe two limitations of your proposed method. (2)
January 2023, AS Unit 3, Q2(b)(i) (3 marks): Draw a table to show the results for the concentration of ions outside the cells. (3)
January 2023, AS Unit 3, Q2(b)(iii) (5 marks): Devise a method that could be used to obtain the data for the pigment shown in the graph. (5)
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)(ii) (1 mark): State the independent variable in this investigation. (1)
January 2023, AS Unit 3, Q3(c)(i) (3 marks): Complete the graph by adding a y-axis scale, y- and x-axes labels and a line of best fit for the yam. The highest percentage change for the yam is 26% and the l
January 2023, AS Unit 3, Q3(c)(ii) (3 marks): The equation for a straight line is y = mx + c. Calculate m for the line of best fit for the potato data and write down the equation for this line. (3)
January 2023, Unit 6, Q1(a) (6 marks): Describe an experiment to investigate the effect of nitrate ion concentration on the rate of growth of these plants. (6)
January 2023, Unit 6, Q2(a) (2 marks): Identify one risk that might be encountered when carrying out this technique and how this risk could be reduced. (2) Risk How this risk could be reduced
January 2023, Unit 6, Q2(c)(i) (2 marks): State two abiotic variables that could affect the growth rate of these bacteria. (2) First variable Second variable
January 2023, Unit 6, Q2(c)(ii) (2 marks): Choose one of the variables you have identified in (c)(i). Describe how this variable could be controlled and the effect it could have on the results if it is n
January 2023, Unit 6, Q3(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
January 2023, Unit 6, Q3(b)(i) (3 marks): Draw a suitable table to display the data and your calculated means for time before extension in mud and sand habitats. (3)
January 2023, Unit 6, Q3(b)(ii) (3 marks): Draw a suitable graph to display your calculated means and the variability of the data, for these two groups of animals. (3)
January 2023, Unit 6, Q3(c)(i) (3 marks): Calculate the value of t. (3) Answer
January 2023, Unit 6, Q3(c)(ii) (3 marks): The table shows the critical values of t for different degrees of freedom. Number of degrees of freedom = (nA – 1) + (nB – 1) Degrees of freedom p = 0.05 p = 0.
January 2023, Unit 6, Q4(a) (3 marks): Describe preliminary practical work that you might undertake to find a suitable method for observing these grasshoppers to provide quantitative results. (3)
January 2023, Unit 6, Q4(b) (8 marks): Devise a detailed method, including how you would control and monitor important variables. (8)
January 2023, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
January 2023, Unit 6, Q4(d) (3 marks): Suggest three limitations of your proposed method. (3)
October 2022, AS Unit 3, Q1(b)(i) (5 marks): Describe a method to allow a quantitative comparison of the vitamin C content of two of these foods. (5)
October 2022, AS Unit 3, Q1(b)(ii) (1 mark): State the independent variable in this investigation. (1)
October 2022, AS Unit 3, Q1(c)(i) (2 marks): Calculate the rate of change of vitamin C content in oranges for the first 3 weeks of storage at 4 °C. Give your answer to 2 significant figures. (2) Answer g d
October 2022, AS Unit 3, Q2(b)(ii) (4 marks): Plot a suitable graph to show the effect of substrate concentration on the initial rate of reaction. (4)
October 2022, AS Unit 3, Q2(c)(i) (3 marks): Draw a suitable table to show the results of this investigation. (3)
October 2022, AS Unit 3, Q3(a)(i) (4 marks): Devise a procedure to provide a valid comparison of the growth of shoots, bulbs and roots of onion plants grown in these three solutions. (4)
October 2022, AS Unit 3, Q3(a)(iv) (3 marks): Describe the information that is needed to decide if any of the differences seen are statistically significant. . (3)
October 2022, Unit 6, Q1(a) (5 marks): Describe an experiment to investigate the effect of temperature on the rate of photosynthesis in Cabomba caroliniana. (5)
October 2022, Unit 6, Q2(a)(i) (1 mark): Describe how 20 cm3 of caffeine solution with a concentration of 200 mg dm–3 could be prepared. (1)
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
October 2022, Unit 6, Q3(a)(i) (2 marks): Identify one risk associated with this investigation and how you could reduce this risk. (2) Risk How to reduce this risk
October 2022, Unit 6, Q3(a)(ii) (1 mark): State a suitable null hypothesis for this investigation. (1)
October 2022, Unit 6, Q3(a)(iii) (3 marks): Plot a suitable graph to show the effect of the concentration of arsenic ions on the percentage germination of wheat grains. (3)
October 2022, Unit 6, Q3(b)(i) (2 marks): Calculate the correlation coefficient (rs) using the formula: (2) ∑ 6 d 2 rs = 1 – ) ( − n n 1 2 Where: Σ = the sum of d = the difference between each pair of r
October 2022, Unit 6, Q3(b)(ii) (3 marks): The table shows some critical values for this statistical test. Number Level of significance (p) of pairs of values 0.10 0.05 0.01 4 1.000 – – 5 0.900 1.000 – 6
October 2022, Unit 6, Q3(c)(ii) (3 marks): Explain how this investigation could be extended to study the effect of arsenic ions on the growth of wheat plants from germinating wheat grains. (3)
October 2022, Unit 6, Q4(a) (3 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (3)
October 2022, Unit 6, Q4(b) (8 marks): Devise a detailed method, including how you would control and monitor important variables. (8)
October 2022, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
October 2022, Unit 6, Q4(d) (3 marks): Suggest three limitations of your proposed method. (3)
June 2022, AS Unit 3, Q1(b)(i) (2 marks): State two dependent variables in this investigation. (2) 1 2
June 2022, AS Unit 3, Q1(c)(i) (3 marks): Describe how you would make 10 cm3 of a 0.4 mol dm−3 sucrose solution using these two solutions. (3)
June 2022, AS Unit 3, Q1(c)(ii) (1 mark): The calcium ion solution is alkaline. State how the pH of the sucrose solutions used in this investigation could be adjusted to a required value. (1)
June 2022, AS Unit 3, Q1(d)(i) (3 marks): Draw a suitable table to show the results for percentage germination. (3)
June 2022, AS Unit 3, Q1(d)(ii) (3 marks): Comment on the conclusion that both percentage germination and mean pollen tube growth have the same optimum sucrose concentration. (3)
June 2022, AS Unit 3, Q2(a) (5 marks): Describe a safe method to observe the stages of mitosis in these roots. (5)
June 2022, AS Unit 3, Q2(c)(i) (4 marks): Plot a suitable graph to show the data in the table. (4)
June 2022, AS Unit 3, Q2(c)(ii) (4 marks): Describe how this investigation could be modified to determine if the differences between the mitotic indices are significant. (4)
June 2022, AS Unit 3, Q3(a) (4 marks): Describe how the data in the table could have been obtained using a 1% starch solution. (4)
June 2022, AS Unit 3, Q3(c) (2 marks): Suggest how this investigation could be adapted to produce quantitative data. (2)
June 2022, Unit 6, Q1(a) (1 mark): Each fish was returned to the source that the eggs came from. Suggest one reason why the scientist thought it was acceptable to carry out this investigation. (1
June 2022, Unit 6, Q1(b)(i) (3 marks): The scientist made a prediction: There is no difference between the observed (O) and expected (E) colour preference of the zebrafish. Using the formula calculat
June 2022, Unit 6, Q1(b)(ii) (1 mark): The critical value of Chi squared was 3.84. Give a conclusion that could be made from this investigation. (1)
June 2022, Unit 6, Q1(c)(i) (1 mark): State one abiotic variable that could affect the results of this investigation. (1) Abiotic variable
June 2022, Unit 6, Q1(c)(ii) (2 marks): Describe how this abiotic variable could be controlled and the effect it could have on the results if it is not controlled. (2) Variable Describe how this varia
June 2022, Unit 6, Q1(d) (1 mark): Suggest why the scientist used each zebrafish only once. (1)
June 2022, Unit 6, Q2(a) (6 marks): Describe an experiment to measure the vitamin C content of each type of fruit. (6)
June 2022, Unit 6, Q2(b) (2 marks): The student found the vitamin C content of the fruits to be: kiwifruit 92.7 mg 100 g–1 guava fruit 223.3 mg 100 g–1 Calculate the percentage difference in vitam
June 2022, Unit 6, Q3(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
June 2022, Unit 6, Q3(b) (3 marks): Draw a suitable table to display the data and your calculated means for these two groups of plants. (3)
June 2022, Unit 6, Q3(c) (3 marks): Plot a suitable graph to show the mean diameter of the stems for each group of plants. Include an indication of the variability of these data. (3)
June 2022, Unit 6, Q3(d)(i) (2 marks): Calculate the value of t. (2) Answer
June 2022, Unit 6, Q3(d)(ii) (2 marks): The table shows the critical values of t for different degrees of freedom. The number of degrees of freedom = (nA – 1) + (nB – 1) Level of significance (p) Degr
June 2022, Unit 6, Q3(e) (2 marks): Explain why it may not be reasonable to draw valid conclusions from the results of this investigation. (2)
June 2022, Unit 6, Q4(a) (3 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (3)
June 2022, Unit 6, Q4(b) (8 marks): Devise a detailed method, including an explanation of how you would control and monitor important variables. (8)
June 2022, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
June 2022, Unit 6, Q4(d) (2 marks): Suggest two limitations of your proposed method. (2)
January 2022, AS Unit 3, Q1(a)(i) (2 marks): State a suitable dependent variable with units for this investigation. (2) Dependent variable Units
January 2022, AS Unit 3, Q2(b)(i) (4 marks): Describe how you could use this apparatus to make a valid comparison of the tensile strength of fibres with different diameters. (4)
January 2022, AS Unit 3, Q2(b)(ii) (4 marks): Some results from this investigation are shown in the table. Diameter / μm Tensile strength / MPa 21 1280 25 830 40 610 43 580 60 390 81 190 84 180 Plot a suita
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(a)(ii) (1 mark): Suggest how the method could be modified to reduce measurement errors. (1)
January 2022, AS Unit 3, Q3(b)(i) (2 marks): Explain how a 0.4 mol dm−3 solution could be made from a 1.0 mol dm−3 sucrose solution. (2)
January 2022, AS Unit 3, Q3(b)(ii) (2 marks): Suggest two properties of sucrose that make it suitable for use in this investigation. (2) 1 2
January 2022, AS Unit 3, Q3(c)(i) (3 marks): Draw a table to show the results at 50 minutes for all six concentrations. (3)
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, Unit 6, Q1(a) (6 marks): Describe an experiment to measure the tensile strength of fibres that have been extracted from these plants. (6)
January 2022, Unit 6, Q2(a) (1 mark): Suggest one reason why the student thought it was ethical to use snails in this investigation. (1)
January 2022, Unit 6, Q2(b) (3 marks): The table shows the results of this investigation. Number of drops of 40 80 120 160 200 water added Total number of snails breaking 1 4 7 9 10 through the membr
January 2022, Unit 6, Q2(c)(i) (2 marks): Give two abiotic variables, other than the independent variable, that could affect this experiment. (2) 1 2
January 2022, Unit 6, Q2(c)(ii) (1 mark): Name one of the variables you have identified in (i). Variable State how this variable could be controlled. (1)
January 2022, Unit 6, Q2(c)(iii) (1 mark): Suggest the effect that not controlling this variable could have on the results. (1)
January 2022, Unit 6, Q2(d) (2 marks): The student decided to repeat the investigation using the same apparatus but adding four drops of water every minute. There was no significant difference in the
January 2022, Unit 6, Q3(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
January 2022, Unit 6, Q3(b) (3 marks): Draw a suitable table to display the raw data and your calculated means for stream A and stream B. (3)
January 2022, Unit 6, Q3(c) (3 marks): Plot a graph to show the mean number of mayfly nymphs for stream A and stream B. Include an indication of the variability of the data. (3)
January 2022, Unit 6, Q3(d)(i) (3 marks): Calculate the value of t. (3) Answer
January 2022, Unit 6, Q3(d)(ii) (3 marks): The table shows the critical values of t for different degrees of freedom. The number of degrees of freedom = (nA − 1) + (nB − 1) Degrees of freedom p = 0.05 p
January 2022, Unit 6, Q3(e) (2 marks): Explain why it may not be reasonable to draw valid conclusions from the results of this investigation. (2)
January 2022, Unit 6, Q4(a) (2 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (2)
January 2022, Unit 6, Q4(b) (8 marks): Devise a detailed method, including how you would control and monitor important variables. (8)
January 2022, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
January 2022, Unit 6, Q4(d) (2 marks): Give two limitations of your proposed method. (2)
October 2021, AS Unit 3, Q1(a)(ii) (3 marks): Describe how the filtrates should have been prepared to allow a valid comparison of the protein content of these foods. (3)
October 2021, AS Unit 3, Q2(a)(i) (3 marks): Explain how using a colorimeter allows valid measurements of light transmitted through the betalain solutions. (3)
October 2021, AS Unit 3, Q2(a)(ii) (2 marks): Temperature and pH affect the rate of leakage of betalain from discs of beetroot. Describe how each of these variables could be kept constant in this investigat
October 2021, AS Unit 3, Q2(b)(i) (3 marks): Draw a table to show the results of this study. (3)
October 2021, AS Unit 3, Q2(c)(ii) (3 marks): Explain how you could modify the method to decide if the difference in colour intensity, at a concentration of 0.002 mmol dm−3, is statistically significant. (3
October 2021, AS Unit 3, Q3(a)(i) (1 mark): State the dependent variable in this investigation. (1)
October 2021, AS Unit 3, Q3(a)(ii) (3 marks): One of the variables that needs to be controlled in this investigation is pH. Describe how a suitable pH could be decided on experimentally. (3)
October 2021, AS Unit 3, Q3(b)(i) (4 marks): Plot a suitable graph to show the relationship between proportional rate of reaction and protease concentration. Join the points with straight lines. (4)
October 2021, AS Unit 3, Q3(c)(ii) (3 marks): Suggest how the initial rate of reaction could be measured in this investigation. (3)
October 2021, AS Unit 3, Q3(d) (2 marks): A student repeated the result for the 2% protease solution. Determine how 1 cm3 of a 2% solution could be obtained from a 5% stock solution of protease. (2)
October 2021, Unit 6, Q1(a) (5 marks): Describe an experiment to investigate the effect of different wavelengths of light on the rate of photosynthesis in Elodea canadensis. (5)
October 2021, 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 2021, 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
October 2021, Unit 6, Q3(a) (2 marks): Identify one risk you might encounter when carrying out this investigation and how you could reduce this risk. (2) Risk How to reduce this risk
October 2021, Unit 6, Q3(b)(i) (1 mark): State a suitable null hypothesis for this investigation. (1)
October 2021, Unit 6, Q3(b)(ii) (2 marks): Plot a suitable graph to show the effect of position on dune on the mean length of marram grass. (2)
October 2021, Unit 6, Q3(c)(i) (2 marks): Calculate the correlation coefficient, rs , using the formula: (2) ∑ 6 d 2 rs = 1 – ( ) n n 2 − 1 Where: Σ = the sum of d = the difference between each pair of
October 2021, Unit 6, Q3(c)(ii) (2 marks): The table shows some critical values for this statistical test. Number Level of significance (p) of pairs of values 0.10 0.05 0.01 4 1.000 – – 5 0.900 1.000 – 6
October 2021, Unit 6, Q3(d) (3 marks): Describe three improvements that could be made to this investigation. (3)
October 2021, Unit 6, Q3(e)(i) (1 mark): Suggest one abiotic factor that might cause the difference in length of the marram grass leaves at these positions on the dune. (1)
October 2021, Unit 6, Q3(e)(ii) (3 marks): Describe how this factor could be measured to produce valid comparisons in this investigation. (3)
October 2021, Unit 6, Q4(a) (3 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (3)
October 2021, Unit 6, Q4(b) (8 marks): Devise a detailed method, including how you would control and monitor important variables. (8)
October 2021, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
October 2021, Unit 6, Q4(d) (3 marks): Suggest three limitations of your proposed method. (3)
June 2021, AS Unit 3, Q1(a) (5 marks): Describe a method that can be used to study the antimicrobial properties of a plant extract. (5)
June 2021, AS Unit 3, Q1(b)(i) (3 marks): Complete the bar chart by labelling the axes and key, using the information in the table. (3)
June 2021, AS Unit 3, Q2(b)(iii) (3 marks): Draw a table to show the data on the effect of root length on mitotic index in seeds treated for 14 days. (3)
June 2021, AS Unit 3, Q2(b)(v) (2 marks): The graph does not show the standard deviations of the means for mitotic index. Describe how the investigation could be modified to allow standard deviations to
June 2021, AS Unit 3, Q3(a) (1 mark): State the dependent variable in this study. (1)
June 2021, AS Unit 3, Q3(b) (2 marks): In this study, the solutions used were maintained at pH 6. Explain why this pH was maintained. (2)
June 2021, AS Unit 3, Q3(c)(i) (5 marks): Draw a graph to show how boric acid concentration affects germination at 4 hours. Join the points with straight lines. (5)
June 2021, AS Unit 3, Q3(d)(ii) (4 marks): Describe how the results shown in the graph could have been obtained. You are provided with a 500 mg dm–3 boric acid solution. (4)
June 2021, Unit 6, Q1(a) (5 marks): Describe an experiment to investigate the effect of calcium ion concentration on the time taken for brine shrimps to hatch. (5)
June 2021, Unit 6, Q1(b)(i) (2 marks): State two abiotic variables, other than the independent variable, that could affect this experiment. (2) First variable Second variable
June 2021, Unit 6, Q1(b)(ii) (2 marks): Choose one of the variables you have identified in (b)(i). Explain how this variable could be controlled. Describe what effect it could have on the results if i
June 2021, Unit 6, Q2(a) (1 mark): Write a suitable null hypothesis for this investigation. (1)
June 2021, Unit 6, Q2(b)(iii) (2 marks): Draw a suitable table to display the results of this investigation. Label the median for both varieties of switchgrass. (2)
June 2021, Unit 6, Q2(c) (3 marks): Draw a graph to show the median biomass for each variety of switch grass. Include an indication of the variability of the data. (3)
June 2021, Unit 6, Q2(d)(i) (2 marks): Calculate the value of U2. (2) Answer
June 2021, Unit 6, Q2(d)(ii) (3 marks): The table shows the critical value of U for probability value of p = 0.05. For the difference to be significant, the smallest calculated U value has to be equal
June 2021, Unit 6, Q2(e) (3 marks): Explain why it may not be reasonable to draw a valid conclusion from the method used in this investigation and the results obtained. (3)
June 2021, Unit 6, Q3(a) (3 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (3)
June 2021, Unit 6, Q3(b) (10 marks): Devise a detailed method, including an explanation of how you would control and monitor important variables. (10)
June 2021, Unit 6, Q3(c) (4 marks): Describe how your results should be recorded, presented and analysed, in order to draw conclusions from your investigation. (4)
June 2021, Unit 6, Q3(d) (4 marks): Suggest four limitations of your proposed method. (4)
January 2021, AS Unit 3, Q2(a)(i) (2 marks): Describe the contents of two more Petri dishes that could be controls for this investigation. (2) Dish 1 Dish 2
January 2021, AS Unit 3, Q2(a)(ii) (2 marks): In this investigation, temperature and pH are variables that need to be controlled. Describe how these variables could be controlled in this investigation. (2)
January 2021, AS Unit 3, Q2(b)(i) (4 marks): Plot a suitable graph to show the results of this investigation. (4)
January 2021, AS Unit 3, Q2(c)(i) (2 marks): Suggest why counting plants will give an inaccurate result for the growth of duckweed after 14 days. Use the information in the photograph to support your answe
January 2021, AS Unit 3, Q2(c)(ii) (4 marks): Explain how this investigation could be modified to provide an accurate measure of the growth rate of duckweed. (4)
January 2021, AS Unit 3, Q3(b)(iii) (3 marks): Athletes can also develop cardiac hypertrophy as a result of exercise programmes (ECH). Individuals with HC and individuals with ECH show changes in the thickne
January 2021, Unit 6, Q1(a) (6 marks): Describe an experiment to investigate the effect of this extract on the rate of pollen tube growth. (6)
January 2021, Unit 6, Q2(b)(i) (2 marks): State two biotic variables that could affect this investigation. (2) First variable Second variable
January 2021, 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 2021, Unit 6, Q3(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
January 2021, Unit 6, Q3(b)(i) (3 marks): Draw a suitable table to display the results and your calculated means for village A and for village B. (3)
January 2021, Unit 6, Q3(b)(ii) (3 marks): Plot a graph to show the mean diameter of the zone of inhibition for village A and for village B. Include an indication of the variability of the results. (3)
January 2021, Unit 6, Q3(b)(iii) (3 marks): A student analysed the data with a t test using the formula ( ) − x x t = A B ( ) ( ) 2 2 S + S A B n n A B where: x– is the mean value for each village n is th
January 2021, Unit 6, Q3(b)(iv) (2 marks): The table shows the critical values of t for different degrees of freedom. The number of degrees of freedom = (nA – 1) + (nB – 1) Degrees of freedom p = 0.05 p
January 2021, Unit 6, Q3(c) (2 marks): Suggest two improvements that could be made to this investigation. (2)
January 2021, Unit 6, Q4(a) (3 marks): Describe preliminary practical work that you might undertake to ensure your proposed method would provide quantitative results. (3)
January 2021, Unit 6, Q4(b) (8 marks): Devise a detailed method, including how you would control and monitor important variables. (8)
January 2021, Unit 6, Q4(c) (3 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (3)
January 2021, Unit 6, Q4(d) (2 marks): Suggest two limitations of your proposed method. (2)
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)(ii) (4 marks): Plot a graph of these results and draw a straight line of best fit through the points. (4)
October 2020, AS Unit 3, Q2(a)(ii) (1 mark): The effect of pH on the initial rate of the reaction catalysed by invertase was investigated at 25 °C. State the independent variable in this investigation. (1)
October 2020, AS Unit 3, Q2(a)(iii) (2 marks): Suggest why the temperature was kept at 25 °C. (2)
October 2020, AS Unit 3, Q2(a)(iv) (1 mark): Name one non‑biological (abiotic) variable, other than temperature, that should be kept constant in this investigation. (1)
October 2020, AS Unit 3, Q2(a)(v) (2 marks): Describe how you would keep the variable you have named in (a)(iv) at a constant value. (2)
October 2020, AS Unit 3, Q2(a)(vii) (3 marks): Suggest how the initial rate of this reaction could be determined. (3)
October 2020, AS Unit 3, Q2(b)(i) (3 marks): Draw a suitable table to show these results. (3)
October 2020, AS Unit 3, Q3(b)(i) (1 mark): Add the scale for carbon dioxide concentration to the graph. (1)
October 2020, AS Unit 3, Q3(b)(ii) (1 mark): Draw the standard deviation for the mean area of the pores 4100 μm2 and 6300 μm2 on the graph. (1)
October 2020, AS Unit 3, Q3(b)(iii) (2 marks): It was concluded that the mean areas of these pores were significantly different. Justify this conclusion. (2)
October 2020, AS Unit 3, Q3(b)(iv) (2 marks): Predict the mean area of pores at a time in the Earth’s history when the carbon dioxide concentration was 6500 ppm. Use the equation y = mx + c, where m = 2.8 a
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(c)(i) (2 marks): State one abiotic and one biotic variable, other than the independent variable, that could affect this experiment. (2) Abiotic variable Biotic variable
October 2020, Unit 6, Q1(c)(ii) (2 marks): Choose one of the variables you have identified in (i). Explain how this variable could be controlled. Describe what effect it could have on the results if it i
October 2020, Unit 6, Q2(a) (1 mark): State a suitable null hypothesis for this investigation. (1)
October 2020, Unit 6, Q2(b)(i) (1 mark): Calculate the percentage difference between the shortest and longest leaves treated with insecticide. (1) Answer %
October 2020, Unit 6, Q2(b)(ii) (3 marks): Calculate the mean length of the leaves for plants treated with insecticide and the mean length of the leaves for plants treated with water. Draw a suitable tab
October 2020, Unit 6, Q2(c) (3 marks): Plot a suitable graph to compare the results of this investigation. (3)
October 2020, Unit 6, Q2(d)(i) (3 marks): The student analysed the data with a t test, using the formula − ( x x ) t = 1 2 ( S ) 2 ( S ) 2 + 1 2 n n 1 2 where: x– is the mean value for each treatment n
October 2020, Unit 6, Q2(d)(ii) (2 marks): The table shows the critical values of t for different degrees of freedom. The number of degrees of freedom = (n1 – 1) + (n2 – 1) Degrees of freedom P = 0.05 P
October 2020, Unit 6, Q2(e) (2 marks): Explain two ways in which this investigation could be improved. (2) 1 2
October 2020, Unit 6, Q3(a) (1 mark): State one safety issue you would need to take into account. (1)
October 2020, Unit 6, Q3(b) (3 marks): Describe the preliminary practical work that you might undertake to ensure your proposed method would provide meaningful data. . (3)
October 2020, Unit 6, Q3(c) (10 marks): Devise a detailed method, including an explanation of how you would control and monitor important variables. (10)
October 2020, Unit 6, Q3(d) (4 marks): Describe how your results should be recorded, presented and analysed in order to draw conclusions from your investigation. (4)
October 2020, Unit 6, Q3(e) (3 marks): Suggest three limitations of your proposed method. (3) 1 2 3
January 2020, AS Unit 3, Q1(b)(iv) (2 marks): The results in the table were plotted as a bar chart. Complete the bar chart by labelling the axes and showing the standard deviation for fresh orange juice and
January 2020, AS Unit 3, Q2(a) (4 marks): Describe a valid method that could be used to compare the breaking force of these fibres. (4)
January 2020, AS Unit 3, Q2(b)(i) (5 marks): Devise a method to determine the cross-sectional area of a fibre, using the following equipment: • a sharp blade • a microscope • a microscope slide and coversl
January 2020, AS Unit 3, Q2(b)(ii) (3 marks): The breaking force and the cross-sectional area were used to determine the tensile strength of fibres from five species of plant. The graph shows the results of
January 2020, AS Unit 3, Q3(a)(i) (1 mark): State the independent variable in this investigation. (1)
January 2020, AS Unit 3, Q3(a)(ii) (2 marks): State two abiotic (environmental) variables that should be controlled in this investigation. (2) 1 2
January 2020, AS Unit 3, Q3(a)(iii) (1 mark): Choose one of the variables you named in (a)(ii) and state how it could be controlled. (1) Variable How it could be controlled
January 2020, AS Unit 3, Q3(a)(iv) (2 marks): Explain why the discs were removed carefully. (2)
January 2020, AS Unit 3, Q3(a)(v) (2 marks): Explain why five discs were used for each concentration of detergent. (2)
January 2020, AS Unit 3, Q3(b)(i) (1 mark): Suggest why this investigation included a 0.0% detergent solution. Use the information in the table to support your answer. (1)
January 2020, AS Unit 3, Q3(b)(ii) (4 marks): Plot a line graph to show the relationship between detergent concentration and percentage of light transmitted. Join the points with straight lines. (4)
January 2020, AS Unit 3, Q3(b)(iv) (3 marks): In a second investigation, the effect of temperature on beetroot cell membrane permeability was studied. The graph shows the results of the second investigation
January 2020, AS Unit 3, Q3(b)(v) (3 marks): Estimate the percentage of light transmitted at 80 °C. Use the information in the graph and your own knowledge to support your answer. (3)
June 2019, AS Unit 3, Q1(a)(i) (1 mark): State the independent variable in this investigation. (1)
June 2019, AS Unit 3, Q1(a)(ii) (1 mark): State one abiotic (environmental) variable that should be controlled in this investigation. (1)
June 2019, AS Unit 3, Q1(a)(iii) (3 marks): Explain why the results might have been affected if the variable you named in (a)(ii) had not been controlled. (3)
June 2019, AS Unit 3, Q1(b)(i) (4 marks): Plot a suitable graph to show the results of this investigation. Join the points with straight lines. (4)
June 2019, AS Unit 3, Q1(b)(ii) (2 marks): These results suggest that the optimum concentration of sucrose for pollen grain germination is 40 g dm–3. Explain how the method could be modified to find the
June 2019, AS Unit 3, Q1(c)(ii) (5 marks): You are provided with a solution containing 500 g dm–3 of sucrose . Devise a procedure to investigate the effect of different concentrations of sucrose on the r
June 2019, AS Unit 3, Q2(a)(ii) (3 marks): Explain how this investigation should be carried out to give a semi‑quantitative estimate of the concentration of the reducing sugars by comparing the colour of
June 2019, AS Unit 3, Q2(a)(iii) (2 marks): It was assumed that the extract contained all the reducing sugars from the food sample. Suggest how this assumption could be tested. (2)
June 2019, AS Unit 3, Q2(b) (2 marks): The table shows the results of the investigation. Food Colour of precipitate apple brick red bread green cashew nut no precipitate potato yellow sweet potato or
June 2019, AS Unit 3, Q2(c)(ii) (4 marks): Devise a procedure to determine the concentration of reducing sugars in a sweet potato. (4)
June 2019, AS Unit 3, Q3(a)(ii) (2 marks): Explain how you could determine suitable concentrations of urea and urease solutions to use in this investigation. (2)
June 2019, AS Unit 3, Q3(b)(i) (4 marks): Draw a suitable table to include the results for the experiment at 60 minutes. (4)

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