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A-LevelBiologyBiological moleculesOct/Nov 2020Paper 1 Q101 Mark

Which row about the structure of proteins is correct? [Figure 10.1]

Aprimary structure: is the number of amino acids present in a protein, tertiary structure: is the result of cross bonding between all the amino acids in the primary structure, quaternary structure: is the polypeptides that link together to form a protein
Bprimary structure: is the order of amino acids present in a protein encoded by DNA, tertiary structure: is the shape formed by folding of a polypeptide and held together by hydrogen bonds, quaternary structure: contains two types of polypeptide that interact forming the shape of a protein
Cprimary structure: is the result of translation of an mRNA molecule by a ribosome into a chain of amino acids, tertiary structure: is the result of ionic and hydrogen bonds, disulfide bridges and hydrophobic interactions between amino acids, quaternary structure: is formed by four polypeptides and an additional reactive group attached to the protein
Dprimary structure: is the sequence of amino acids in a protein coded by an mRNA molecule, tertiary structure: is formed as a result of interaction of the side chains of amino acids in the primary structure, quaternary structure: is formed by the linking together of more than one polypeptide to form a protein

✓ Correct Answer

The correct answer is D: primary structure: is the sequence of amino acids in a protein coded by an mRNA molecule, tertiary structure: is formed as a result of interaction of the side chains of amino acids in the primary structure, quaternary structure: is formed by the linking together of more than one polypeptide to form a protein

📋 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 2020 examination, Paper 1 Variant 2.

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