Pearson Edexcel International GCSE in Biology · 4BI1 · Free · no account needed
The Carbon and Nitrogen Cycles — exam questions
10 original Incandio exam-style questions on the Carbon and Nitrogen Cycles, 25 marks, about 25 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 The Carbon and Nitrogen Cycles — 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
8 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
- Name (1–2 marks)
- the correct term, spelled recognisably
- Give (1–2 marks)
- a short factual answer drawn from recall or from the data
- 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
- 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
- Suggest (1–3 marks)
- a plausible answer applying taught biology to a situation not taught
- Calculate (1–3 marks)
- a numerical answer, with working where the tariff implies steps
- Discuss (3–6 marks)
- an account that puts more than one consideration side by side and reaches a position
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 4.10 · 4.11. 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 10 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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Table 1 — nitrate concentration in the soil of two fields, measured in spring. Field A was planted with clover the previous year; field B was left as bare ploughed soil. Field Previous year Nitrate / mg per kg of soil A clover crop 68 B bare ploughed soil 21 (a)
(1)Calculate
Calculate how many times more nitrate field A contains than field B.
Table 1 — nitrate concentration in the soil of two fields, measured in spring. Field A was planted with clover the previous year; field B was left as bare ploughed soil. Field Previous year Nitrate / mg per kg of soil A clover crop 68 B bare ploughed soil 21 (b)
(3)Explain
Explain the difference in nitrate concentration between the two fields.
Table 1 — nitrate concentration in the soil of two fields, measured in spring. Field A was planted with clover the previous year; field B was left as bare ploughed soil. Field Previous year Nitrate / mg per kg of soil A clover crop 68 B bare ploughed soil 21 (c)
(2)Suggest
Suggest one advantage to a farmer of growing clover rather than adding nitrate fertiliser.
Table 1 — nitrate concentration in the soil of two fields, measured in spring. Field A was planted with clover the previous year; field B was left as bare ploughed soil. Field Previous year Nitrate / mg per kg of soil A clover crop 68 B bare ploughed soil 21 (Total for Question 1 = 6 marks)
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(1)Which
Which process removes carbon dioxide from the atmosphere?
Process A respiration B combustion C photosynthesis D decomposition (Total for Question 2 = 1 mark)
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(1)Name
Name the type of bacteria that converts nitrogen gas from the air into nitrogen compounds in the soil.
Figure 2 — the nitrogen cycle. (Total for Question 3 = 1 mark)
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(2)Give
Give two processes that return carbon dioxide to the atmosphere.
Figure 1 — the carbon cycle. (Total for Question 4 = 2 marks)
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(4)Describe
Describe how a carbon atom in the air can end up in a fossil fuel.
Figure 1 — the carbon cycle. (Total for Question 5 = 4 marks)
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(2)Explain
Explain why plants cannot use the nitrogen in the air directly.
Figure 2 — the nitrogen cycle. (Total for Question 6 = 2 marks)
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(3)Suggest
Suggest why waterlogged soil often contains very little nitrate.
(Total for Question 7 = 3 marks)
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(6)Discuss
Discuss the part that decomposers play in the carbon cycle and in the nitrogen cycle, and what would happen to both if they stopped working.
(Total for Question 8 = 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 — 10 questions, marked on Incandio against the authored scheme, with the mistake you actually made named.
- Teach it — explain the Carbon and Nitrogen Cycles to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Antoine Lavoisier over three rounds, marked against descriptors you can read first.
Completely free. No subscriptions, no paywalls, no account needed to start.
Back to the lesson
- The Carbon and Nitrogen Cycles — The same atoms, used again and again — and the four bacteria that do the work nothing else can.
- All of Incandio Biology · Incandio Exam Practice