Pearson Edexcel International GCSE in Biology · 4BI1 · Free · no account needed
Alleles, Genotype and Phenotype — exam questions
10 original Incandio exam-style questions on Alleles, Genotype and Phenotype, 21 marks, about 21 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 Alleles, Genotype and Phenotype — 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 what is meant by (1–2 marks)
- the definition
- 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 3.20 · 3.19 · 3.21. 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 — flower colour in a species where the allele for red petals (C^R) and the allele for white petals (C^W) are codominant. Three crosses were carried out. Cross Parent genotypes Offspring phenotypes 1 C^R C^R × C^W C^W all pink 2 C^R C^W × C^R C^W red, pink and white 3 C^R C^W × C^W C^W pink and white only (a)
(1)Give
Give the genotype of a pink-flowered plant, using Table 1.
Table 1 — flower colour in a species where the allele for red petals (C^R) and the allele for white petals (C^W) are codominant. Three crosses were carried out. Cross Parent genotypes Offspring phenotypes 1 C^R C^R × C^W C^W all pink 2 C^R C^W × C^R C^W red, pink and white 3 C^R C^W × C^W C^W pink and white only (b)
(3)Explain
Explain why cross 2 produced red and white plants as well as pink ones.
Table 1 — flower colour in a species where the allele for red petals (C^R) and the allele for white petals (C^W) are codominant. Three crosses were carried out. Cross Parent genotypes Offspring phenotypes 1 C^R C^R × C^W C^W all pink 2 C^R C^W × C^R C^W red, pink and white 3 C^R C^W × C^W C^W pink and white only (c)
(2)Suggest
Suggest why cross 3 produced no red plants at all.
Table 1 — flower colour in a species where the allele for red petals (C^R) and the allele for white petals (C^W) are codominant. Three crosses were carried out. Cross Parent genotypes Offspring phenotypes 1 C^R C^R × C^W C^W all pink 2 C^R C^W × C^R C^W red, pink and white 3 C^R C^W × C^W C^W pink and white only (Total for Question 1 = 6 marks)
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(1)Which
Which term describes the alleles an organism carries?
Term A phenotype B genotype C genome D gamete (Total for Question 2 = 1 mark)
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(1)State what is meant by
State what is meant by an allele.
(Total for Question 3 = 1 mark)
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(1)Give
Give the meaning of the term homozygous.
(Total for Question 4 = 1 mark)
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(3)Explain
Explain why two organisms that look identical may have different genotypes.
(Total for Question 5 = 3 marks)
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(2)State what is meant by
State what is meant by codominance.
(Total for Question 6 = 2 marks)
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(3)Suggest
A recessive allele causes a serious illness in people who inherit two copies of it. Suggest why the allele has not disappeared from the population.
(Total for Question 7 = 3 marks)
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(4)Explain
Explain why two people can have the same phenotype for a characteristic but different genotypes, and why this matters for their children.
(Total for Question 8 = 4 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 Alleles, Genotype and Phenotype to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Charles Darwin 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
- Alleles, Genotype and Phenotype — Two copies of every gene, and the rules that decide which one you can see — including the case where you can see both.
- All of Incandio Biology · Incandio Exam Practice