A-LevelBiologyBiological moleculesOct/Nov 2019Paper 1 Q121 Mark
Which row about the structure of proteins is correct?
Aprimary structure: is the number of amino acids present in a protein, secondary structure: is the left-handed spiral formed by the primary structure, quaternary structure: is the sub-unit polypeptides that link together to form a protein
Bprimary structure: is the order of amino acids present in a protein encoded by DNA, secondary structure: is the coiling of a chain of amino acids to form a β-pleated sheet or α-helix, 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, secondary structure: occurs because of attraction between hydrogen and oxygen atoms in the peptide bonds, 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, secondary structure: is formed by hydrogen bonding between amino acids forming 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. This question tests the candidate's understanding of biological molecules within the Biologysyllabus. The examiner's mark scheme requires...
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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...
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