Q8(b). Haemocyanin: active site, colours and functions
Draw the active site structure of haemocyanin (Hc) in deoxyhaemocyanin and oxyhaemocyanin forms, and write the colour of haemocyanin in these two forms. Write the functions of haemocyanin.
Answer in brief
The active site is a pair of copper atoms, each held by three histidine nitrogens, with no haem; deoxy form two Cu(I), colourless; oxy form two Cu(II) bridged side-on by peroxide, blue; it reversibly carries O₂ in molluscs and arthropods.
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The full model answer
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Covershaemocyaninoxygen transport proteincopper proteinside-on peroxidebioinorganic chemistrydeoxyhaemocyanin
All parts of Question 8
- 8(a) The more stable linkage isomer of a cyanide-bridged complex10 marks
- 8(b) Haemocyanin: active site, colours and functions10 marks
- 8(c) Stationary and branching chain reactions; conditions for explosion10 marks
- 8(d) Steady-state approximation; photochemical H₂ + Cl₂; quantum yield10 marks
- 8(e) Langmuir isotherm and the kinetics of surface reactions10 marks