Oxidation involves electron transfer. In most cases, electrons are transferred from
chemicals that do not want them (electron donors) to chemicals that desire them (electron
acceptors). In figure 14.3, the process of oxidation is illustrated with a mechanical
example. An electron donor (the hand) places the electron (a very heavy ball) on the ramp.
The electron rolls down the ramp and activates the lever which lifts the weight that
represents ATP in figure 14.4. In this way, the potential energy of the electron is used
to do work. In the mechanical example, it lifts the weight. In life, the energy released
by oxidation reactions is used to create ATP.
Figure 14.3: A Mechanical Example of Oxidation
Figure 14.4: The Electron Does Work When it Lifts the Weight
Figure14.5: Final State - The Weight Can Now Perform Work
In figure 14.5, the weight is left on top of a smaller ramp. It too can
now perform work. In life, the work is often maximized by using a series of several
electron donors and acceptors. Bacteria in particular are very good at using many
different chemicals for both acceptor and donors. This allows them to consume all kinds of
chemicals for food. In higher life, the primary electron donor is glucose (sugar) and the
final acceptor is oxygen.
next: ATP created by a
Proton Gradient
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