Archaebacteria is an organism that converts the carbon dioxode to methane by a process called methanogenesis. In this process H2 is the donor of reducing equivalents and Co2 is the electron acceptor. In archabacteria,the electron transport chain can be run in reverse. In this direction, the energy in the proton gradientis used to drive the reduction of CO2 to HCOOH and ultimatley th CH4 rather than reducing power driving the formation of a proton gradient as in typical electron transport. The H2 provides the reducing equivalents that are further transferred via other electron carriers.

a. Which way are the protons flowing during reverse electron transport chain? From the acidic outside to the basic inside or from the basic inside to the acidic outside?

b. During the normal electron transport chain which way are the protons floeing? From the acidic outside to the basic inside or from the basic inside to the acidic outside?

c.During the normal electron transport chain what is the trend inreduction potentials and what do the vaues mean?