Testing for biological: past paper questions
Real questions on testing for biological
The newest 20 of 211 written questions. Open one to see it on the real paper.
- 9700/21 · October/November 2025 · Q3b(i)[1]
Iodine solution was used to confirm that starch was not present in extract E. State the colour observed when iodine solution was added to a sample of extract E. The student added a small drop of a dilute starch solution and a solution of glucose 1‑phosphate to a test‑tube containing extract E. Samples of the reaction m...
See it on the paper → - 9700/21 · October/November 2025 · Q3b(ii)[3]
Explain the results shown in Fig. 3.2.
See it on the paper → - 9700/21 · October/November 2025 · Q3b(iii)[1]
After 12 minutes, the student added a solution containing phosphate ions to the reaction mixture. The student continued taking samples every minute, adding iodine solution to each sample. The absorbance of the solution in each of these samples was measured. The results showed that the absorbance decreased over time. Su...
See it on the paper → - 9700/22 · October/November 2025 · Q1c(ii)[2]
Describe the formation of tissue fluid in the capillary network of the villus.
See it on the paper → - 9700/43 · October/November 2025 · Q3a(ii)[2]
Suggest two explanations for the differences in appearance of chromatograms A and B in Fig. 3.1.
See it on the paper → - 9700/43 · October/November 2025 · Q3a(iii)[1]
The student found some different R f values for the chloroplast pigments of spinach in a scientific paper. The values in the scientific paper were different from the reference values that the student originally used to identify the pigments on chromatograms A and B in Fig. 3.1. Suggest one reason, other than measuremen...
See it on the paper → - 9700/43 · October/November 2025 · Q3b[4]
Fig. 3.2 shows the absorption spectra of some chloroplast pigments. key chlorophyll a chlorophyll b carotenoids (β-carotene and xanthophyll) 90 60 percentage absorption 30 0 400 blue 500 600 wavelength of light / nm red 700 Fig. 3.2 Use Fig. 3.2 to compare the similarities and differences between the absorption spectra...
See it on the paper → - 9700/51 · October/November 2025 · Q1c(i)[2]
State a suitable control that the student could use, and explain why the student decided to include a control in the investigation. control explanation
See it on the paper → - 9700/51 · October/November 2025 · Q1c(ii)[7]
Describe a method the student could use to investigate the effect of juglone on: • • the percentage of cucumber seeds that germinate the growth of each cucumber seedling 10 days after the appearance of the seedling above the soil. The description of your method should be set out in a logical way and be detailed enough...
See it on the paper → - 9700/51 · October/November 2025 · Q1d(i)[2]
The student used the t-test to analyse the results. The t-test is appropriate for the number of seeds that were used. Suggest two other reasons why the t-test is an appropriate statistical test to use for this investigation.
See it on the paper → - 9700/51 · October/November 2025 · Q1d(ii)[3]
The null hypothesis for this t-test was: There is no difference between the time taken for seeds to germinate when treated with juglone and the time taken for seeds to germinate when not treated with juglone. The calculated value of t was 2.090. The student compared 2.090 to the values in Table 1.1. Table 1.1 probabili...
See it on the paper → - 9700/51 · October/November 2025 · Q2b(i)[2]
State the type of data represented by the species of bacterium and the lowest nitrite concentration in Fig. 2.1. species of bacterium
See it on the paper → - 9700/51 · October/November 2025 · Q2b(ii)[3]
The 2 species of Salmonella shown in Fig. 2.1 are closely related. Calculate the percentage difference between the results shown in Fig. 2.1 for the 2 species of Salmonella. Show your working.
See it on the paper → - 9700/51 · October/November 2025 · Q2b(iii)[1]
Use Fig. 2.1 to state: • • the species of bacterium that is most affected by nitrite ions the species of bacterium that is least affected by nitrite ions. most affected
See it on the paper → - 9700/51 · October/November 2025 · Q2c[4]
A student looked at the results and stated: Consuming a lot of nitrites would improve the health of people because it would help to prevent diseases in the digestive system caused by pathogenic bacteria. Suggest four reasons why this conclusion might not be valid.
See it on the paper → - 9700/52 · October/November 2025 · Q1a(i)[2]
State the independent and dependent variables in the investigation. independent dependent
See it on the paper → - 9700/52 · October/November 2025 · Q1a(ii)[2]
The student prepared 20 cm 3 of 2.5%, 5.0% and 10.0% sucrose solutions from a 20.0% w/v stock solution. Complete the description of the student’s dilution method for the 2.5% and 5.0% sucrose solutions by writing the correct volumes in the following sentences. The student mixed cm 3 of 20.0% sucrose stock solution with...
See it on the paper → - 9700/52 · October/November 2025 · Q1a(iii)[5]
The student observed stomata on the microscope slides using the high‑power objective lens. Outline a method the student could use to investigate the effect of the sucrose solutions in Table 1.1 on the width of stomata in the leaves of plantain lily. Your method should be set out in a logical order and be detailed enoug...
See it on the paper → - 9700/52 · October/November 2025 · Q1a(iv)[2]
Predict the effect of increasing the sucrose concentration from 0.0% to 20.0% on the width of stomata in the leaves of plantain lily. Explain your prediction. prediction explanation
See it on the paper → - 9700/52 · October/November 2025 · Q1b(i)[4]
Use Fig. 1.3 to calculate the stomatal density on the lower epidermis. Use the equation: Give your answer to the nearest whole number and show your working. area = πr 2 and π = 3.14 –2
See it on the paper →
What examiners said
Most candidates correctly calculated Simpson’s index of diversity (D) to three significant figures. A few candidates expressed D to an incorrect number of significant figures.
— Examiner report, February/March 2025, 9700/52 Q1(b) (Cambridge)
This question was well answered. Many candidates described a suitable method to investigate changes in the species diversity of the plants in the grey dune ecosystem during the ten-year period after conservation practices were introduced. Several developed thorough plans that included details of appropriate sampling techniques. Random or systematic sampling techniques were both valid approaches....
— Examiner report, February/March 2025, 9700/52 Q1(c)(ii) (Cambridge)
Strong responses identified two conditions from the details provided that supported the use of Spearman’s rank correlation in this investigation. Many recognised that the data could be ranked and that the coffee farms were chosen at random. Fewer appreciated that the observations were paired.
— Examiner report, February/March 2025, 9700/52 Q2(a) (Cambridge)
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