An experiment is performed in which the rate constant for electron transfer is measured as a function of distance by attaching an electron donor and acceptor to pieces of DNA of varying length. The measured rate constant for electron transfer as a function of separation distance is as follows: 

a. Determine the value for β that defines the distance dependence of the electron transfer rate constant.

b. It has been proposed that DNA can serve as an electron €œÏ€ -way€ that facilitates electron transfer over long distances. Using the rate constant at 17 Ã… presented earlier, what value of β would result in the rate of electron transfer decreasing by only a factor of 10 at a separation distance of 23Ã…?

2.01 107 17 2.07 x 10 2.10 x 108 kep (s=1) Distance () 204 14 23 32