OCR GCSE Biology A: Working scientifically: planning, recording, presenting and evaluating practical data (J247) – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover the working scientifically section (5e) of the OCR GCSE (9-1) Gateway Science Biology A (J247) specification, Version 4.0 (August 2026): practical skills 2a to 2d and statements 1.2, 1.3 and 1.4. None of it is Higher Tier only.

Links: study guide, revision notes, OCR GCSE Biology hub, printable checklist and the free 10-minute diagnostics.

Questions

1. A student soaks 20 pea seeds in each of three dishes kept at 10 °C, 20 °C and 30 °C, and counts how many have germinated after four days. Identify the independent variable and the dependent variable, and name one control variable with a way of keeping it constant. [3]

2. Protease enzymes are proteins that digest egg white. Using the idea of the active site, write a hypothesis and a prediction for an investigation comparing the digestion of egg white at 40 °C and at 80 °C. [3]

3. A student counts the leaves with holes on each of ten plants: 6, 3, 8, 5, 3, 7, 3, 9, 4, 2. Calculate the mean, median, mode and range. [4]

4. The number of stomata in five fields of view of a leaf impression was 31, 29, 33, 58 and 30. (a) Identify the anomalous result and suggest one possible cause. [2] (b) Calculate the mean without the anomaly, to 1 decimal place. [2] (c) Suggest one way to check whether the anomaly is genuine. [1]

5. Two students each measure the temperature of a beaker of ice and water, which is really 0.0 °C. Student X records 2.1, 2.0 and 2.2 °C. Student Y records -0.6, 0.5 and 0.2 °C. (a) State which student’s readings are more precise and give evidence from the range. [2] (b) Compare the accuracy of the two means and name the type of error that most likely affected student X. [2]

6. (a) Name the best form of graph or chart for each data set. [3]

• (i) The number of seeds in each of five mass classes (0.10 to 0.19 g, 0.20 to 0.29 g and so on).
• (ii) The rate of an enzyme reaction at 10, 20, 30, 40 and 50 °C.
• (iii) The number of woodlice found in four named habitats.

(b) A graph’s x axis is 12 cm long and must cover 0 to 30 minutes. Suggest a suitable scale and explain why 7 minutes per cm would be a poor choice. [2]

7. A line of best fit for gas volume against time passes through (2 min, 3.6 cm³) and (12 min, 21.6 cm³). (a) Calculate the gradient. [3] (b) State what the gradient represents, with its unit. [1]

8. A drawing of a root hair cell is 45 mm long. The real cell is 150 µm long. (a) Calculate the magnification of the drawing. [3] (b) Another cell is 0.12 mm long. How long is it in a drawing at the same magnification? [2]

9. (a) A seedling grows from 7.2 cm to 10.0 cm. Calculate the percentage increase in height to 2 significant figures. [3] (b) A bacterium is 0.0000025 m long. Write this in standard form, then in µm. [2]

10. A field measures 30 m by 20 m. A student places ten 0.25 m² quadrats and counts daisy plants: 4, 2, 0, 3, 1, 5, 2, 3, 2, 3. (a) Explain why the quadrats should be placed at random. [1] (b) Calculate the mean number of daisies per quadrat. [1] (c) Calculate the density in daisies per m². [1] (d) Estimate the number of daisies in the field. [1] (e) Suggest one change that would make the estimate more reliable. [1]

11. Equal-looking cubes of beetroot, cut by eye, are placed in tubes of water for 5 minutes at different temperatures, one cube per temperature. A colorimeter measures how much red pigment has leaked into the water. Absorbance: 20 °C 0.05; 30 °C 0.08; 40 °C 0.12; 50 °C 0.45; 60 °C 1.10; 70 °C 1.32. (a) Describe the pattern, quoting data. [3] (b) Identify three weaknesses in the method and suggest an improvement for each. [3] (c) Explain the results in terms of the cell membrane. [2]

12. Plan an investigation into the effect of pH on the activity of amylase, which digests starch. Include a hypothesis, how you will vary and measure, the control variables, repeats, one safety precaution, and how you will set out your results. [8]

Answers

1. Independent variable: temperature [1]. Dependent variable: the number (or percentage) of seeds germinated after four days [1]. Control, for example: the same volume of water in each dish, kept constant by measuring it with a measuring cylinder (or: the same pea variety, taken from one packet) [1]. [3] Examiner insight: A control variable named without saying how it is held constant tends to earn less than one with a method attached.

2. Hypothesis: a very high temperature changes the shape of the protease active site, so egg white is digested more slowly [1]. Prediction: egg white at 80 °C will be digested slower than (or not at all compared with) egg white at 40 °C [1]. Explanation: the enzyme is denatured, so the substrate no longer fits the active site [1]. [3] Examiner insight: A prediction states what you expect to see; a hypothesis gives the scientific reason, so keep the two apart.

3. Total = 50, so mean = 50 / 10 = 5.0 [1]. Ordered list is 2, 3, 3, 3, 4, 5, 6, 7, 8, 9, so median = (4 + 5) / 2 = 4.5 [1]. Mode = 3 [1]. Range = 9 - 2 = 7 [1]. [4] Examiner insight: Order the values before choosing the median.

4. (a) 58 is the anomaly [1], possibly because a different area was counted or two stomata were counted twice, or a counting slip [1]. (b) 31 + 29 + 33 + 30 = 123 [1]; 123 / 4 = 30.8 [1]. (c) Repeat the count on that field of view, or count more fields [1]. [5] Examiner insight: Say why you believe a value is anomalous and what you did with it; deleting it without comment loses the explanation.

5. (a) Student X is more precise [1] because X’s range is 0.2 °C but Y’s range is 1.1 °C [1]. (b) X’s mean is 2.1 °C, a long way from 0.0 °C, while Y’s mean is 0.03 °C, so Y is more accurate [1]. X’s readings are all shifted the same way, so the error is systematic, such as a thermometer that reads too high [1]. [4] Examiner insight: Precision is about the spread of repeats and accuracy is about the distance of the mean from the true value, so quote numbers for each.

6. (a) (i) histogram, bars touching, because the mass classes are continuous [1]. (ii) line graph, because temperature is a continuous variable [1]. (iii) bar chart, with gaps, because the habitats are categories [1]. (b) 2.5 minutes per cm uses the full 12 cm (12 x 2.5 = 30) [1]. 7 minutes per cm makes plotting awkward and wastes or overruns the axis (30 / 7 is not a whole number of centimetres) [1]. [5] Examiner insight: Give the reason for each chart type, since a bare name leaves nothing to support it.

7. (a) Change in volume = 21.6 - 3.6 = 18.0 cm³ [1]. Change in time = 12 - 2 = 10 min [1]. Gradient = 18.0 / 10 = 1.8 [1]. (b) The rate of gas production, 1.8 cm³ per min [1]. [4] Examiner insight: Read points from the line itself, and include the unit.

8. (a) 45 mm = 45 000 µm [1]. Magnification = 45 000 / 150 [1] = x300 [1]. (b) 0.12 mm = 120 µm [1]. Drawn length = 120 x 300 = 36 000 µm = 36 mm [1]. [5] Examiner insight: Convert both lengths to the same unit before dividing; an unconverted ratio is the most common source of a wrong power of ten.

9. (a) Increase = 10.0 - 7.2 = 2.8 cm [1]. 2.8 / 7.2 x 100 = 38.9% [1]. To 2 significant figures = 39% [1]. (b) 2.5 x 10⁻⁶ m [1] = 2.5 µm [1]. [5] Examiner insight: Round only at the end; rounding 2.8 / 7.2 early can change the second significant figure.

10. (a) Random placement avoids bias towards areas that look good, so the sample represents the whole field [1]. (b) 25 / 10 = 2.5 per quadrat [1]. (c) 2.5 / 0.25 = 10 per m² [1]. (d) Area = 30 x 20 = 600 m², so 10 x 600 = 6000 daisies [1]. (e) Use more quadrats (for example 30), which reduces the effect of chance [1]. [5] Examiner insight: “Estimate” is the right word for part (d); the field was only sampled, not counted.

11. (a) Absorbance changes little from 20 °C to 40 °C (0.05 to 0.12) [1]. It rises sharply between 40 °C and 60 °C (0.12 to 1.10) [1]. It rises less between 60 °C and 70 °C (1.10 to 1.32) [1]. (b) Cubes cut by eye vary in surface area, so cut with a cork borer to one length [1]. Only one cube per temperature, so repeat each and take a mean [1]. Water bath temperature may drift, so keep a thermometer in the tube and check it [1]. (c) High temperature damages the membrane (protein parts are denatured) [1], so it becomes more permeable and pigment leaks out [1]. [8] Examiner insight: In evaluations, a weakness plus its effect plus a specific fix gives a clear answer; “do it more carefully” gives nothing to credit.

12. Hypothesis: amylase works fastest at a particular pH and slower either side of it, because pH changes the shape of the active site [1]. Independent variable: pH, using buffer solutions at five values, for example pH 4, 5, 6, 7 and 8 [1]. Dependent variable: the time taken for starch to disappear, tested with iodine solution on a spotting tile every 30 seconds [1]. Controls, two of: temperature kept at 35 °C in a water bath; same volume and concentration of starch; same volume and concentration of amylase [2]. Repeat each pH at least three times and calculate a mean [1]. Safety: wear eye protection and wipe up iodine spills (or take care with hot water) [1]. Results table: pH in the first column, times for each repeat, then the mean time, with units in the headings [1]. [8] Examiner insight: Name the apparatus and the values you will use; “change the pH and see” gives little to credit.

Where marks are usually lost

• Naming a control variable without saying how it is kept constant.
• Writing a prediction and calling it a hypothesis.
• Finding a median without ordering the values first.
• Leaving an anomaly in a mean, or deleting it without explanation.
• Calling a result accurate because the repeats agree.
• Choosing a bar chart for two continuous variables.
• Mixing mm and µm in a magnification calculation.
• Leaving units off a rate or a gradient.
• Describing a graph without quoting values from it.
• Giving a vague improvement such as “be more careful” instead of a specific change.

Next steps

• Review the revision notes and the study guide.
• Check your coverage on the OCR GCSE Biology hub and the printable checklist.
• Take one of the free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

OCR GCSE (9-1) Gateway Science Biology A (J247), Version 4.0 (August 2026), first assessment 2018, published by OCR: section 5e Working scientifically (statements 1.2, 1.3, 1.4 and 2a to 2d), section 5f mathematical skills, and Topic B7 Practical skills.