CAIE A Level Biology 9700 · Biological molecules
Haemoglobin is a globular protein with quaternary structure. When a solution of haemoglobin is heated above 60°C, it loses its ability to bind oxygen and becomes insoluble. Explain the changes in bonding that occur during this denaturation, and describe how these changes affect the different levels of protein structure (primary, secondary, tertiary, quaternary).
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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