BIO2 Reading 10

Why are redox reactions important in biology?

Electron transfer is involved in the building, breakdown, and conversion of molecules as well as the transfer of energy

Reduction

Gain of electrons

Reduced State

Condition of electron carriers after accepting electrons; have the potential to donate electrons

Reducing Agent/Reductant

Reduces another species (electron donor); is itself oxidized

Oxidation

Loss of electrons

Oxidized State

Condition of electron carriers after donating electrons; have the potential to accept electrons

Oxidizing Agent/Oxidant

Oxidizes another species (electron acceptor); is itself reduced

Reduction Potential

Empirically determined quantitative measure of the ability of a molecule to gain or lose electrons; as electronegativity is to atoms, reduction potential is to molecules

Standard Reduction Potential (E˚')

Relative reduction potential intrinsic to each molecule measured and reported in volts (V); lower E˚' -> better electron donor, higher E˚' -> better electron acceptor

Redox Tower

Table of standard reduction potentials organized in half reactions as [Oxidized/Reduced]

How do you find the ΔE˚' and what does this value imply?

ΔE˚' = E˚'[oxidant] - E˚'[reductant]

Higher ΔE˚' -> more spontaneous reaction

How can ΔG˚' be determined from ΔE˚'?

ΔG˚' = -nFΔE˚' where n = mol electrons and F = Faraday's constant (96.485 kJ/(V*mol))

(Inversely proportional)

How do the number of C-H bonds relate to how reduced a molecule is?

More C-H bonds -> more reduced