Pearson Edexcel International GCSE in Biology · 4BI1 · Free · no account needed
DNA, Genes and Chromosomes — exam questions
10 original Incandio exam-style questions on DNA, Genes and Chromosomes, 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 DNA, Genes and Chromosomes — 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 what is meant by (1–2 marks)
- the definition
- 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
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 3.16 · 3.14 · 3.15. 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 — the percentage of each base measured in the DNA of three organisms. Organism Adenine / % Thymine / % Cytosine / % Guanine / % Human 30.4 30.1 19.6 19.9 Yeast 31.3 32.9 17.1 18.7 Bacterium 24.7 23.6 26.0 25.7 (a)
(2)Describe
Describe the pattern in the percentages shown in Table 1.
Table 1 — the percentage of each base measured in the DNA of three organisms. Organism Adenine / % Thymine / % Cytosine / % Guanine / % Human 30.4 30.1 19.6 19.9 Yeast 31.3 32.9 17.1 18.7 Bacterium 24.7 23.6 26.0 25.7 (b)
(3)Explain
Explain the pattern you have described in terms of the structure of DNA.
Table 1 — the percentage of each base measured in the DNA of three organisms. Organism Adenine / % Thymine / % Cytosine / % Guanine / % Human 30.4 30.1 19.6 19.9 Yeast 31.3 32.9 17.1 18.7 Bacterium 24.7 23.6 26.0 25.7 (c)
(1)Suggest
Suggest what a scientist should conclude about a sample whose DNA was measured as 24% adenine and 31% thymine.
Table 1 — the percentage of each base measured in the DNA of three organisms. Organism Adenine / % Thymine / % Cytosine / % Guanine / % Human 30.4 30.1 19.6 19.9 Yeast 31.3 32.9 17.1 18.7 Bacterium 24.7 23.6 26.0 25.7 (Total for Question 1 = 6 marks)
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(1)Which
Which base pairs with cytosine in DNA?
Base A adenine B thymine C guanine D uracil (Total for Question 2 = 1 mark)
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(1)State what is meant by
State what is meant by a gene.
(Total for Question 3 = 1 mark)
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(1)Give
Give the number of chromosomes in a normal human body cell.
number of chromosomes = ............................
(Total for Question 4 = 1 mark)
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(3)Describe
Describe how a genome, a chromosome, a gene and a base are related to one another.
Figure 1 — the structure of a short length of DNA. (Total for Question 5 = 3 marks)
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(2)Explain
Explain why the two strands of a DNA molecule are described as complementary.
Figure 1 — the structure of a short length of DNA. (Total for Question 6 = 2 marks)
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(3)Suggest
Human cells and mouse cells contain almost the same total quantity of DNA. Suggest why the two organisms are nevertheless very different.
(Total for Question 7 = 3 marks)
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(4)Explain
Explain the relationship between a chromosome, a gene, DNA and a protein.
(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 DNA, Genes and Chromosomes to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Gregor Mendel 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
- DNA, Genes and Chromosomes — One molecule at four magnifications — and the pairing rule that makes it possible to copy information without understanding it.
- All of Incandio Biology · Incandio Exam Practice