plumiDNA, RNA and replication: Edexcel International A Level Biology questions
Every Edexcel International A Level Biology exam question on DNA, RNA and replication (specification points 2.9–2.10), 2019–2025, with its mark scheme and examiner’s report.
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Q5(a)
The whole paper ↗Q5(c)(i)
The whole paper ↗Q5(c)(ii)
The whole paper ↗Q5(a)
The whole paper ↗Q5(b)
The whole paper ↗Q5(c)
The whole paper ↗Q2(a)(i)
The whole paper ↗Your answerQ2(a)(ii)
The whole paper ↗Your answerQ6(c)(ii)
The whole paper ↗Q1(a)
The whole paper ↗Q1(b)
The whole paper ↗Q6(a)(i)
The whole paper ↗Q6(a)(ii)
The whole paper ↗Q1(a)(iii)
The whole paper ↗Your answerQ1(b)
The whole paper ↗Q7(a)(i)
The whole paper ↗Your answerQ7(a)(ii)
The whole paper ↗Your answerQ8(a)
The whole paper ↗Q8(b)(i)
The whole paper ↗Q8(b)(ii)
The whole paper ↗
All 55 questions on DNA, RNA and replication, as a list
- June 2025, AS Unit 1, Q5(a) (2 marks): When a cell is preparing to divide, DNA synthesis takes place. Explain how two identical molecules of DNA are produced. (2)
- June 2025, AS Unit 1, Q5(c)(i) (2 marks): Give one advantage and one disadvantage of using a Voronoi diagram to present this information. (2) Advantage Disadvantage
- June 2025, AS Unit 1, Q5(c)(ii) (6 marks): The proportions of these molecules change as a bacterial cell prepares to divide, as it divides into two new bacterial cells and as each new bacterial cell grow
- January 2025, AS Unit 1, Q5(a) (2 marks): State the meaning of the term semi‑conservative replication. (2)
- January 2025, AS Unit 1, Q5(b) (2 marks): Describe the role of DNA polymerase in the process of DNA replication. (2)
- January 2025, AS Unit 1, Q5(c) (6 marks): Meselson and Stahl used mononucleotides made with either heavy nitrogen (N15) or light nitrogen (N14) in their experiments. The flowchart summarises part of one
- June 2024, AS Unit 1, Q2(a)(i) (1 mark): The base labelled Q is thymine. Which is the base labelled P? (1) A adenine B cytosine C guanine D uracil
- June 2024, AS Unit 1, Q2(a)(ii) (1 mark): Which row of the table identifies the bonds labelled R, S and T? (1) R S T A covalent phosphodiester hydrogen B hydrogen covalent phosphodiester C hydrogen phos
- January 2024, AS Unit 1, Q6(c)(ii) (3 marks): Describe the structure of a mRNA molecule. (3)
- October 2023, AS Unit 1, Q1(a) (5 marks): Read through the following passage about DNA. Complete the passage by writing the most appropriate word or words on the dotted lines. (5) A strand of DNA is com
- October 2023, AS Unit 1, Q1(b) (3 marks): The table shows some components of DNA mononucleotides and RNA mononucleotides and shapes that can be used to represent them. Component Shapes bond thymine T U
- October 2023, Unit 4, Q6(a)(i) (1 mark): Which diagram shows a mononucleotide of DNA? (1) Key Sugar Phosphate Base Bond A B C D
- October 2023, Unit 4, Q6(a)(ii) (1 mark): Name the bond that joins nucleotides together in a strand of DNA. (1)
- October 2023, Unit 5, Q1(a)(iii) (1 mark): Which bond joins nucleotides together in a single strand of DNA? (1) A hydrogen B ionic C peptide D phosphodiester
- June 2023, AS Unit 1, Q1(b) (3 marks): The diagram shows part of a tRNA molecule. Compare and contrast the structure of an mRNA molecule with that of a tRNA molecule. (3)
- January 2023, Unit 4, Q7(a)(i) (1 mark): Which row of the table identifies the bonds Q and R? (1) Bond Q Bond R A covalent hydrogen B hydrogen covalent C hydrogen phosphodiester D phosphodiester covale
- January 2023, Unit 4, Q7(a)(ii) (1 mark): Which is a negatively charged part of a DNA molecule? (1) A P B R C S D T
- October 2022, AS Unit 1, Q8(a) (3 marks): The diagrams show the structure of the four bases. Guanine and adenine have two ring structures, cytosine and thymine have one ring structure. H N H O CH3 N N N
- October 2022, AS Unit 1, Q8(b)(i) (1 mark): Calculate the mean mass of a base pair. Express your answer in standard form. (1) Answer Da
- October 2022, AS Unit 1, Q8(b)(ii) (2 marks): Calculate the total mass of DNA produced after three cell divisions. Give your answer in grams, where 1 dalton = 1.67 × 10–24 grams. (2) Answer g
- October 2022, AS Unit 1, Q8(c)(i) (3 marks): Complete the diagram to show the results of this investigation. Use the dotted lines to help you position the bands on the diagram. The first one has been done
- October 2022, AS Unit 1, Q8(c)(ii) (2 marks): One competing theory was the conservative theory. The diagram shows the conservative theory for the replication of DNA. after stage 1 after stage 2 Complete the
- October 2022, AS Unit 1, Q8(c)(iii) (2 marks): Another competing theory was the dispersive theory. The diagram shows the dispersive theory. after stage 1 after stage 2 Complete the diagram to show the positi
- January 2022, AS Unit 1, Q3(a) (3 marks): Describe the structure of a nucleotide pair. (3)
- January 2022, AS Unit 1, Q3(b) (2 marks): Before a cell can divide, the DNA molecule has to replicate. This takes place in the S phase of the cell cycle. Human DNA replicates at a rate of 50 nucleotides
- January 2022, AS Unit 1, Q3(c)(i) (2 marks): Explain the role of DNA polymerase in a replication bubble. Use the information in the diagram and your own knowledge to support your answer. (2)
- January 2022, AS Unit 1, Q3(c)(ii) (3 marks): In human cells, S phase lasts about 10 hours. Suggest why each DNA molecule is replicated using many replication bubbles. (3)
- January 2022, Unit 4, Q5(a) (2 marks): Give two differences between the structure of nuclear DNA and mtDNA. (2)
- October 2021, AS Unit 1, Q6(b)(i) (2 marks): The diagram shows part of the base sequence on one of the RNA strands. Complete the diagram to show the base sequence on the other RNA strand. (2) C A G A A A G
- October 2021, AS Unit 1, Q6(b)(ii) (3 marks): Describe the bonding in this double-stranded RNA molecule. (3)
- October 2021, Unit 4, Q2(b)(i) (1 mark): The diagram shows part of the base sequence in the negative RNA strand. Complete the diagram to show the corresponding base sequence in the positive RNA strand.
- October 2021, Unit 5, Q6(b) (2 marks): Describe the role of DNA polymerase in DNA replication during cell proliferation. (2)
- June 2021, Unit 4, Q1(b)(i) (1 mark): Which does P represent? (1) A the maximum genome size on a bar chart B the maximum genome size on a histogram C mode genome size on a bar chart D mode genome si
- June 2021, Unit 4, Q1(b)(ii) (1 mark): One genome size is missing from the graph for class 2 mosses. Calculate the frequency of this genome size. (1) Answer
- June 2021, Unit 4, Q1(b)(iii) (1 mark): The mean value for the genome size of class 1 mosses was 0.449 a.u. and the mean value for class 2 mosses was 0.920 a.u. Calculate the ratio of the genome size
- January 2021, AS Unit 1, Q1(a)(i) (1 mark): Which diagram shows a mononucleotide? (1) A B C D
- January 2021, AS Unit 1, Q1(a)(ii) (1 mark): Which diagram shows two components joined by a phosphodiester bond? (1) A B C D
- January 2021, AS Unit 1, Q1(a)(iii) (1 mark): Which diagram shows complementary base pairing? (1) A B C D
- January 2021, AS Unit 1, Q1(b)(i) (3 marks): The table shows some statements about the new complementary DNA strand and the mRNA strand synthesised using this sequence of bases. For each statement, put one
- January 2021, Unit 4, Q7(d)(i) (2 marks): Give two examples of circular DNA found in cells. (2)
- January 2021, Unit 4, Q7(d)(ii) (2 marks): Give two differences between the structure of circular DNA and that of linear DNA, other than their shapes. (2)
- October 2020, AS Unit 1, Q4(a)(i) (1 mark): Draw a circle around one mononucleotide that includes the base labelled R. (1)
- October 2020, AS Unit 1, Q4(a)(ii) (1 mark): Which row of the table identifies the bonds labelled S, T and U? (1) S T U A hydrogen phosphodiester covalent B hydrogen covalent phosphodiester C phosphodieste
- October 2020, AS Unit 1, Q4(a)(iii) (1 mark): The base labelled P is adenine. Which is the base labelled Q? (1) A cytosine B guanine C thymine D uracil
- October 2020, AS Unit 1, Q4(b)(i) (5 marks): Complete the diagram to show the results of this experiment. Use the dotted lines to help you to position the bands on the diagram. The first one has been done
- October 2020, AS Unit 1, Q4(b)(ii) (1 mark): The experiments of Meselson and Stahl disproved the dispersive theory of DNA replication. The diagram shows the expected results if the dispersive theory was co
- January 2020, AS Unit 1, Q1 (6 marks): Polynucleotides include DNA and messenger RNA (mRNA). Some components of polynucleotides are found in both DNA and mRNA. Other components are found only in DNA
- June 2019, AS Unit 1, Q4(a)(i) (2 marks): State what is meant by the term semi-conservative replication. (2)
- June 2019, AS Unit 1, Q4(a)(ii) (1 mark): Name one enzyme involved in semi-conservative replication. (1)
- June 2019, AS Unit 1, Q4(a)(iii) (2 marks): Explain the importance of semi-conservative replication in the production of new cells. (2)
- June 2019, AS Unit 1, Q4(b) (3 marks): The flow chart summarises part of one experiment performed by Meselson and Stahl. Stage 1 Bacteria grown for several generations in culture medium containing he
- January 2019, AS Unit 1, Q3(a) (3 marks): Each single strand of a DNA molecule is synthesised from mononucleotides. Draw a diagram to show two mononucleotides joined together in a single strand of DNA.
- January 2019, AS Unit 1, Q3(b)(i) (1 mark): Calculate the distance between one base and the next base on one strand of DNA. Give your answer to an appropriate number of significant figures. (1) Answer nm
- January 2019, AS Unit 1, Q3(b)(ii) (2 marks): The diagram shows the structure of thymine and four other bases, P, Q, R and S. Bases P and S can form three hydrogen bonds each and bases Q and R can form two
- January 2019, AS Unit 1, Q3(c) (4 marks): Compare and contrast the structure of messenger RNA (mRNA) with the structure of transfer RNA (tRNA). (4)
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