CAIE A Level Biology 9700 · Immunity
A researcher is investigating the immune response to a newly discovered bacterium, Corynebacterium novum. The bacterium has a unique surface protein, antigen X. Antibodies produced against antigen X are able to neutralise the bacterium and mark it for destruction by phagocytes. Describe how the structure of an antibody enables it to bind specifically to antigen X and carry out these functions.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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