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A-LevelBiologyBiological moleculesOct/Nov 2022Paper 1 Q111 Mark

Silk moth caterpillars have been genetically modified to produce a mixture of their own silk and the much stronger spider silk of the golden orb web spider. The spider silk polypeptide chain has many repeated sequences of two amino acids, glycine and alanine, arranged in a crystalline structure. [Diagram] What correctly describes the structure of spider silk?

Aprimary protein structure with regions of α-helices
Bsecondary protein structure with regions of β-pleated sheets
Ctertiary protein structure with regions of α-helices
Dquaternary protein structure with regions of β-pleated sheets

✓ Correct Answer

The correct answer is B: secondary protein structure with regions of β-pleated sheets

📋 Examiner Report & Trap Analysis

Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...

🎯 Mark Scheme Breakdown

Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.

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About This A-Level Biology Question

Topic

This multiple-choice question tests Biological molecules in A-Level Biology (syllabus code 9700). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Biology Oct/Nov 2022 examination, Paper 1 Variant 2.

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