A-LevelBiologyImmunity9700/12 · May/June 2019 · Q401 Mark

The diagrams show three different types of antibody structure. [Figure: Diagrams of IgG, IgA, IgM antibody structures] Which row is correct?

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AIgG: one binding site for an antigen molecule, IgA: two light chains, IgM: two heavy chains

BIgG: two heavy chains, IgA: four binding sites for antigen molecules, IgM: five hinge regions

CIgG: two hinge regions, IgA: four heavy chains, IgM: five light chains

DIgG: two light chains, IgA: four hinge regions, IgM: ten binding sites for antigen molecules

✓ Correct answer

B: IgG: two heavy chains, IgA: four binding sites for antigen molecules, IgM: five hinge regions

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