The photosynthetic reaction centre of the purple photosynthetic bacterium Rhodopseudomonas viridis contains a number of bound cofactors that participate in electron transfer reactions. The following table shows data compiled by Moser et al. (Nature 355,796 (1992)) on the rate constants for electron transfer between different cofactors and their edge-to-edge distances:

(BChl, bacteriochlorophyll; BChl2, bacteriochlorophyll dimer, functionally distinct from BChl; BPh, bacteriophaeophytin; QA and QB' quinone molecules bound to two distinct sites; cyt c559, a cytochrome bound to the reaction centre complex). Are these data in agreement with the behaviour predicted by eqn 24.831 If so, evaluate the value of p.

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Reaction BChl-BPh BPh→BChl; r/nm 0.48 1.58 x 10¹2 Reaction Q-Qa r/nm 1.35 kls 3.98 x 10² 0.95 3.98 x 10° Q→ BChl 2.24 63.1 BPhQ₁ cyt C59 →→ BChl 1.23 1.58 x 108 0.96 1.00 x 10⁰