Pearson Edexcel International GCSE in Biology · 4BI1 · Free · no account needed
Enzymes: Catalysts With a Shape — exam questions
13 original Incandio exam-style questions on Enzymes: Catalysts With a Shape, 36 marks, about 36 minutes of writing. Each one carries the command word, the tariff and the specification statement it assesses, exactly as a paper presents them. This is an original Incandio practice question, written to reflect the structure and demands of the qualification. It is not an official Pearson Edexcel past-paper question.
This is the practice set for Enzymes: Catalysts With a Shape — the lesson that teaches it. Read the lesson first if the idea is new; come here when you want to find out whether you can turn it into marks. Completely free, no account needed to read.
What these questions ask of you
9 command words run through this set, and on Pearson Edexcel International GCSE Biology each one means something precise. Answering the wrong command is the commonest way a candidate who understands the lesson still loses the mark.
- Which (1 mark)
- one option chosen from the set given
- State (1 mark)
- one precise fact, no justification
- Explain (2–4 marks)
- a causal chain — WHY it happens, each link a separate marking point Misread as: describing what happens without giving the reason it happens
- Calculate (1–3 marks)
- a numerical answer, with working where the tariff implies steps
- Describe (2–4 marks)
- developed, linked statements of WHAT happens — no reason required, but detail is Misread as: giving one bare statement where the tariff asked for a developed account
- Suggest (1–3 marks)
- a plausible answer applying taught biology to a situation not taught
- Give (1–2 marks)
- a short factual answer drawn from recall or from the data
- Design (4–6 marks)
- a workable method: variables, control, measurement, repeats
- Evaluate (3–6 marks)
- evidence on both sides, then a judgement that follows from it
Assessed on Paper 1 (4BI1/1B) and Paper 2 (4BI1/2B), against AO1, AO2, AO3.
Where these sit in the specification
Pearson Edexcel International GCSE Biology (4BI1) — statements 2.10 · 2.12 · 2.11. Incandio is aligned to this specification; it is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording.
The 13 questions
Answer them on paper, then open the lesson's exam practice to have them marked. The mark scheme, the accepted and rejected answers and the annotated model answer are in Incandio and are not printed here — an answer beside its question is not practice.
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A student investigated how temperature affects the enzyme amylase. She mixed 2 cm³ of amylase solution with 2 cm³ of starch solution in a test tube, held the tube in a water bath, and every 20 seconds removed one drop and tested it with iodine solution. She recorded the time at which the iodine solution stopped turning blue-black.
Table 1 — the time taken for the starch to disappear at each temperature. Each temperature was tested three times and the mean is shown. Temperature / °C Mean time for starch to disappear / s 10 312 20 168 30 96 40 74 50 139 60 no change after 600 (a)
(1)Give
Give the independent variable in this investigation.
A student investigated how temperature affects the enzyme amylase. She mixed 2 cm³ of amylase solution with 2 cm³ of starch solution in a test tube, held the tube in a water bath, and every 20 seconds removed one drop and tested it with iodine solution. She recorded the time at which the iodine solution stopped turning blue-black.
Table 1 — the time taken for the starch to disappear at each temperature. Each temperature was tested three times and the mean is shown. Temperature / °C Mean time for starch to disappear / s 10 312 20 168 30 96 40 74 50 139 60 no change after 600 (b)
(2)Calculate
The rate of reaction can be found using rate = 1000 ÷ time. Calculate the rate of reaction at 30 °C. Give your answer to 2 significant figures.
A student investigated how temperature affects the enzyme amylase. She mixed 2 cm³ of amylase solution with 2 cm³ of starch solution in a test tube, held the tube in a water bath, and every 20 seconds removed one drop and tested it with iodine solution. She recorded the time at which the iodine solution stopped turning blue-black.
Table 1 — the time taken for the starch to disappear at each temperature. Each temperature was tested three times and the mean is shown. Temperature / °C Mean time for starch to disappear / s 10 312 20 168 30 96 40 74 50 139 60 no change after 600 rate of reaction = ............................
(c)
(4)Explain
Explain the results the student obtained between 40 °C and 60 °C.
A student investigated how temperature affects the enzyme amylase. She mixed 2 cm³ of amylase solution with 2 cm³ of starch solution in a test tube, held the tube in a water bath, and every 20 seconds removed one drop and tested it with iodine solution. She recorded the time at which the iodine solution stopped turning blue-black.
Table 1 — the time taken for the starch to disappear at each temperature. Each temperature was tested three times and the mean is shown. Temperature / °C Mean time for starch to disappear / s 10 312 20 168 30 96 40 74 50 139 60 no change after 600 (Total for Question 1 = 7 marks)
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(1)Which
Which row of the table correctly describes an enzyme?
Made of Used up in the reaction? A protein yes B protein no C carbohydrate no D lipid yes (Total for Question 2 = 1 mark)
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(1)State
State what is meant by the active site of an enzyme.
(Total for Question 3 = 1 mark)
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(2)Explain
Amylase breaks down starch but has no effect on protein. Explain why.
(Total for Question 4 = 2 marks)
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(2)Calculate
In one experiment the starch took 240 seconds to disappear at 25 °C and 80 seconds to disappear at 35 °C. Calculate how many times faster the reaction was at 35 °C than at 25 °C.
(Total for Question 5 = 2 marks)
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(3)Explain
Explain why the rate of an enzyme-controlled reaction increases as the temperature is raised from 10 °C to 30 °C.
(Total for Question 6 = 3 marks)
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(3)Describe
A student is investigating the effect of temperature on the rate at which amylase breaks down starch. Describe three variables the student must keep the same, and state why each one matters.
(Total for Question 7 = 3 marks)
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(2)Suggest
Bacteria living in hot volcanic springs at 85 °C produce enzymes that work normally at that temperature. Human enzymes stop working at 60 °C. Suggest an explanation for this difference.
(Total for Question 8 = 2 marks)
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(5)Design
A gardener claims that the enzyme in a shop-bought compost accelerator works best at 35 °C. Design an investigation, using amylase and starch, that would test whether an enzyme's optimum temperature really is 35 °C.
(Total for Question 9 = 5 marks)
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(4)Evaluate
A student tested amylase at 30 °C and at 70 °C only, found the reaction was faster at 30 °C, and concluded that 30 °C is the optimum temperature for amylase. Evaluate this conclusion.
(Total for Question 10 = 4 marks)
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(6)Design
Design an experiment to find the optimum pH for the digestion of starch by amylase.
(Total for Question 11 = 6 marks)
Have them marked, then defend the answer
Practice tells you the mark; teaching it back tells you whether you understand it. On Incandio a topic counts as mastered only once you have taught it and defended it.
- Mark these questions — 13 questions, marked on Incandio against the authored scheme, with the mistake you actually made named.
- Teach it — explain Enzymes: Catalysts With a Shape to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Emil Fischer over three rounds, marked against descriptors you can read first.
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Back to the lesson
- Enzymes: Catalysts With a Shape — Why a protein with a hole in it speeds up a reaction, and why heat destroys that ability permanently.
- All of Incandio Biology · Incandio Exam Practice