Enzymes: past paper questions
Real questions on enzymes
The newest 20 of 39 written questions, plus 22 multiple-choice. Open one to see it on the real paper.
- 5129/31 · October/November 2025 · Q1c[3]
The student tests each food for the presence of protein. State the name and the initial colour of the chemical used to test for protein and the final colour of the chemical that shows that protein is present in a food. name of chemical initial colour
See it on the paper → - 5129/31 · October/November 2025 · Q2a[1]
Fig. 2.1 shows the filtration of the mixture and water. A residue test tube filtrate Fig. 2.1 State the name of apparatus A. funnel mixture of solids and water
See it on the paper → - 5129/31 · October/November 2025 · Q2b[1]
The residue is the green solid from the original mixture. Explain why the residue does not contain any of the white solid.
See it on the paper → - 5129/31 · October/November 2025 · Q2e(i)[1]
Describe the observation that shows that a gas is produced when dilute sulfuric acid is added to the residue.
See it on the paper → - 5129/32 · October/November 2025 · Q1b(iii)[2]
Suggest an improvement to the procedure to find a more accurate value of the temperature at which lipase digests fat most quickly.
See it on the paper → - 5129/32 · October/November 2025 · Q1c[3]
The student knows that lipase is a protein. State the name, initial colour and final colour of the chemical used to show that lipase is still present in the mixture after the fat has been digested. name of chemical initial colour
See it on the paper → - 5129/21 · May/June 2025 · Q4[3]
On Fig. 4.1, draw three lines from the box on the left to three different boxes on the right to make three correct sentences about enzymes. … are biological catalysts. … are denatured at 37 °C. … are proteins. Enzymes in the human body … … always change shape after reacting with a substrate. … act on specific substrate...
See it on the paper → - 5129/22 · October/November 2024 · Q1c[3]
Fig. 1.2 shows how the activity of four different enzymes A, B, C and D varies with pH. C A B enzyme activity 0 D 1 2 3 4 5 6 7 8 9 10 11 12 pH Fig. 1.2 Place a tick (✓) in three boxes in Table 1.1 to identify three correct conclusions that can be made from the information in Fig. 1.2. Table 1.1 Both enzyme A and enzym...
See it on the paper → - 5129/31 · October/November 2024 · Q1b(i)[1]
From your results in Table 1.1, determine the temperature at which the amylase works most quickly to break down starch. temperature at which amylase works most quickly = °C (i)
See it on the paper → - 5129/31 · October/November 2024 · Q1b(ii)[1]
Suggest how the student can improve the repeatability of the result. (ii)
See it on the paper → - 5129/31 · October/November 2024 · Q1b(iii)[1]
Other than improving repeatability, suggest how the student can change the procedure to improve the accuracy of the result.
See it on the paper → - 5129/32 · October/November 2024 · Q1c[2]
Measure: the distance a between point F and point G a = mm the distance b between point E and F. P 1 transparent block P 2 A B D C P 3 P 4 eye Fig. 1.1
See it on the paper → - 5129/32 · October/November 2024 · Q1d[2]
A teacher says that for any pair of values θ i and θ r , the ratio sin θ i is equal to a constant k. sin θ r For this transparent block k = 1.54. The constant k may also be calculated using the equation: k = 0.34 b a Use your values of a and b in part (c) in this equation to calculate another value of k. k = Record you...
See it on the paper → - 5129/32 · October/November 2024 · Q1e[1]
The two values of k can be considered to be equal within the limits of experimental accuracy if they are within 10% of each other. State whether your results show that the two values obtained for k are equal. Tick (3) one box. Yes, my k values are within 10% of each other, so they are equal. No, my k values are not wit...
See it on the paper → - 5129/32 · October/November 2024 · Q2a(i)[2]
Name the apparatus used to measure 25.0 cm 3 of water and the apparatus used to measure the temperature. apparatus used to measure 25.0 cm 3 of water
See it on the paper → - 5129/32 · October/November 2024 · Q2a(ii)[1]
Fig. 2.1 shows parts of the apparatus used to measure the temperatures at 30 s and 150 s. °C °C 30 30 20 20 10 10 temperature at 30 s temperature at 150 s Fig. 2.1 Use the information in Fig. 2.1 to complete Table 2.1 on page 6. temperature / °C 0 21.5 60 15.0 90 15.0 120 16.0 150 180 18.5 240 21.0 time / s Table 2.1
See it on the paper → - 5129/32 · October/November 2024 · Q2a(iii)[1]
Plot your temperature readings from (a)(ii) on the grid in Fig. 2.2. 23 22 temperature / °C 21 20 19 18 17 16 15 13 12 0 50 100 150 200 250 300 time / s 14
See it on the paper → - 5129/32 · October/November 2024 · Q2a(iv)[2]
On the grid in Fig. 2.2, draw one straight line of best fit using the first three points only. Draw another straight line of best fit using the last five points only. Extend both lines of best fit so that they meet.
See it on the paper → - 5129/32 · October/November 2024 · Q2a(v)[1]
The point where both best-fit lines meet is the lowest temperature that the mixture reaches. State the lowest temperature that the mixture reaches. lowest temperature = °C
See it on the paper → - 5129/32 · May/June 2024 · Q4[7]
Fig. 4.1 shows a cooked bird’s egg. egg white egg yolk Fig. 4.1 The egg white is broken down by the enzyme protease to produce a colourless liquid. A student states: “The egg white is broken down faster in acidic solutions than in neutral or alkaline solutions.” Plan an investigation to test whether this statement is c...
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What examiners said
In this question candidates drew lines between six structures (cells and tissues) in plants and their functions. Five functions are shown and the rubric explains that each can be used once, more than once, or not at all. Candidates should be guided by the number of marks for the question, in this case six marks. However, many candidates only drew five lines. The common error was to omit the connec...
— Examiner report, October/November 2023, 5129/21 Q2 (Cambridge)
Most candidates knew some aspects of the carbon cycle and correctly linked it with combustion and respiration. A common error was to misunderstand the role of decomposers in returning carbon dioxide to the atmosphere as they respire.
— Examiner report, October/November 2023, 5129/21 Q14(a) (Cambridge)
Candidates should know that a measurement is described as accurate if it is close to the true value. Many candidates knew that the results should be repeated but failed to gain the mark for knowing that the experiment needed to be repeated at smaller intervals around the approximate value to gain a value closer to the true temperature at which the starch was broken down.
— Examiner report, October/November 2023, 5129/32 Q1(b)(ii) (Cambridge)
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