Pearson Edexcel International GCSE in Biology · 4BI1 · Free · no account needed
Yoghurt and the Industrial Fermenter — exam questions
10 original Incandio exam-style questions on Yoghurt and the Industrial Fermenter, 24 marks, about 24 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 Yoghurt and the Industrial Fermenter — 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
6 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
- Give (1–2 marks)
- a short factual answer drawn from recall or from the data
- 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
- 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 5.7 · 5.8. 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 — pH and lactose concentration measured during the production of yoghurt at 45 °C. Time / hours pH Lactose / g per 100 g 0 6.7 4.8 1 6.2 4.4 2 5.4 3.5 3 4.6 2.7 4 4.4 2.4 5 4.4 2.3 (a)
(1)Give
Give the time at which the pH stopped falling in Table 1.
Table 1 — pH and lactose concentration measured during the production of yoghurt at 45 °C. Time / hours pH Lactose / g per 100 g 0 6.7 4.8 1 6.2 4.4 2 5.4 3.5 3 4.6 2.7 4 4.4 2.4 5 4.4 2.3 time = ............................ hours
(b)
(3)Explain
Explain why the lactose concentration and the pH both fall as the yoghurt is made.
Table 1 — pH and lactose concentration measured during the production of yoghurt at 45 °C. Time / hours pH Lactose / g per 100 g 0 6.7 4.8 1 6.2 4.4 2 5.4 3.5 3 4.6 2.7 4 4.4 2.4 5 4.4 2.3 (c)
(2)Suggest
Suggest why both measurements stop changing after four hours although lactose still remains.
Table 1 — pH and lactose concentration measured during the production of yoghurt at 45 °C. Time / hours pH Lactose / g per 100 g 0 6.7 4.8 1 6.2 4.4 2 5.4 3.5 3 4.6 2.7 4 4.4 2.4 5 4.4 2.3 (Total for Question 1 = 6 marks)
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(1)Which
Which substance does Lactobacillus produce from the sugar in milk?
Substance A ethanol B lactic acid C carbon dioxide D glucose (Total for Question 2 = 1 mark)
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(1)State
State why the milk is heat-treated before the bacteria are added.
(Total for Question 3 = 1 mark)
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(2)Give
Give two conditions that must be controlled inside an industrial fermenter.
Figure 1 — an industrial fermenter. (Total for Question 4 = 2 marks)
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(3)Explain
Explain why a large industrial fermenter needs a cooling jacket rather than a heater.
Figure 1 — an industrial fermenter. (Total for Question 5 = 3 marks)
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(2)Explain
Explain why the contents of a fermenter are stirred continuously.
Figure 1 — an industrial fermenter. (Total for Question 6 = 2 marks)
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(3)Suggest
Suggest why a single contaminating microorganism can ruin an entire batch in a fermenter.
(Total for Question 7 = 3 marks)
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(6)Discuss
Discuss why an industrial fermenter is designed with a stirrer, a cooling jacket and probes, and what would happen if any one of them failed.
(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 Yoghurt and the Industrial Fermenter to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Élie Metchnikoff over three rounds, marked against descriptors you can read first.
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Back to the lesson
- Yoghurt and the Industrial Fermenter — Bacteria turned into a manufacturing process — and the vessel built to give them the best conditions they will ever have.
- All of Incandio Biology · Incandio Exam Practice