Pearson Edexcel International GCSE in Biology · 4BI1 · Free · no account needed
The Placenta and the Amniotic Fluid — exam questions
9 original Incandio exam-style questions on the Placenta and the Amniotic Fluid, 19 marks, about 19 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 Placenta and the Amniotic Fluid — 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
5 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
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 3.11 · 3.12. 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 9 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 — the concentration of four substances in the mother's blood and in the fetal blood, measured at the placenta. Substance Mother's blood arriving / arbitrary units Fetal blood arriving / arbitrary units Oxygen 98 31 Glucose 85 62 Carbon dioxide 42 61 Urea 6 19 (a)
(1)Give
Give the two substances in Table 1 whose concentration is higher in the fetal blood.
Table 1 — the concentration of four substances in the mother's blood and in the fetal blood, measured at the placenta. Substance Mother's blood arriving / arbitrary units Fetal blood arriving / arbitrary units Oxygen 98 31 Glucose 85 62 Carbon dioxide 42 61 Urea 6 19 (b)
(3)Explain
Explain how the figures in Table 1 account for the direction each substance moves.
Table 1 — the concentration of four substances in the mother's blood and in the fetal blood, measured at the placenta. Substance Mother's blood arriving / arbitrary units Fetal blood arriving / arbitrary units Oxygen 98 31 Glucose 85 62 Carbon dioxide 42 61 Urea 6 19 (c)
(2)Suggest
Suggest what would happen to the fetal oxygen figure if the mother became short of oxygen at high altitude.
Table 1 — the concentration of four substances in the mother's blood and in the fetal blood, measured at the placenta. Substance Mother's blood arriving / arbitrary units Fetal blood arriving / arbitrary units Oxygen 98 31 Glucose 85 62 Carbon dioxide 42 61 Urea 6 19 (Total for Question 1 = 6 marks)
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(1)Which
Which substance passes from the fetus to the mother across the placenta?
Substance A glucose B oxygen C urea D amino acids (Total for Question 2 = 1 mark)
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(1)State
State one function of the amniotic fluid.
(Total for Question 3 = 1 mark)
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(2)Give
Give two substances that pass from the mother's blood to the fetal blood.
(Total for Question 4 = 2 marks)
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(4)Explain
Explain how the placenta is adapted for exchanging substances between two circulations.
(Total for Question 5 = 4 marks)
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(2)Explain
Explain why a fetus can develop normally although it is surrounded by liquid.
(Total for Question 6 = 2 marks)
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(3)Suggest
Some drugs and viruses are small enough to cross the placenta. Suggest why this can harm a fetus even when the mother is unaffected.
(Total for Question 7 = 3 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 — 9 questions, marked on Incandio against the authored scheme, with the mistake you actually made named.
- Teach it — explain the Placenta and the Amniotic Fluid to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Marcello Malpighi over three rounds, marked against descriptors you can read first.
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Back to the lesson
- The Placenta and the Amniotic Fluid — An exchange surface with a constraint no other one has: two bloodstreams that must trade materials without ever mixing.
- All of Incandio Biology · Incandio Exam Practice