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Structure of nucleic acids and replication of DNA

Biology5 questions

5 past-paper questions on Structure of nucleic acids and replication of DNA

9700/22 · October/November 20244 marks
Identify and describe the DNA-RNA nucleotide pair shown in Fig. 3.1. You may add labels and annotations to Fig. 3.1 if you wish.
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9700/23 · October/November 20244 marks
Describe the sequence of events that occurs at the stage shown in Fig. 3.3 to extend the synthesised strand.
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9700/23 · May/June 20243 marks
Describe three ways in which the structure of messenger RNA (mRNA) differs from the structure of DNA. In each of your answers,…
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9700/23 · October/November 20243 marks
The two strands in a molecule of DNA are described as antiparallel. With reference to Fig. 3.2 and Fig. 3.3, state what is meant…
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9700/23 · May/June 20242 marks
State and explain which DNA base pair is most similar to the synthetic base pairs in Fig. 6.1.
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Worked example

What a lost mark actually looks like

This answer reaches the right coordinates and still drops a mark — the conclusion is stated, but never justified. Examiners pay for the reasoning, not the answer.

MARKED

80%

Strong

M1dy/dx = 3x^2 - 12x + 9M1 earned
M1(x - 1) $(x - 3) = 0$ M1 earned
A1 $x = 1$ or $x = 3$ A1 earned
B1(1, 5) is a maximum and (3, 1) is a minimumB1 not earned

B1 — withheld
You stated the nature of each point correctly, but stated it without justification. This mark needs the reasoning shown — either evaluate the second derivative (d²y/dx² = 6x − 12, giving −6 at $x = 1$ and +6 at $x = 3$ ) or show a sign change of dy/dx either side of each point. An unsupported assertion earns nothing here even when the conclusion is right.

Structure of nucleic acids and replication of DNA (9700) past-paper questions — marked instantly

These are real Cambridge Biology past-paper questions on Structure of nucleic acids and replication of DNA. Open one, attempt it, then upload your working — MarkScheme grades it against the official 9700 mark scheme so you see exactly where the marks are won and lost on this topic.

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Frequently asked questions

How many Structure of nucleic acids and replication of DNA questions are there for 9700?: This page collects 5 recent Cambridge Biology (9700) past-paper questions tagged to Structure of nucleic acids and replication of DNA. Each links straight to instant marking against the official 9700 scheme.
How are Structure of nucleic acids and replication of DNA answers marked?: Type or photograph your working and MarkScheme scores it against the real 9700 mark scheme for this topic — method, accuracy and any band descriptors — so you see exactly where the marks are.
Where can I learn Structure of nucleic acids and replication of DNA first?: Start with the free Biology lesson on Structure of nucleic acids and replication of DNA, then come back and drill past-paper questions under timed conditions.