BIOCHEM FINAL - Redox chemistry

to show oxidation and reduction separately and that electron transfer can occur without direct contact.

Why are redox reactions written as half-reactions?

ΔG’° = −nFΔE’°.

What is the relationship between ΔG’° and ΔE’°?

ΔG = ΔG’° + RT ln Q.

How is ΔG calculated for redox reactions?

The proton motive force - the tendency of species to attract electrons

What provides energy in redox reactions?

two chemical species that interconvert by gaining or losing electrons

What is a conjugate redox pair?

Hydride removal (dehydrogenation) catalyzed by dehydrogenases

What is a common type of biological oxidation of carbon?

1. direct electron transfer

2. hydrogen atom transfer

3. hydride transfer

4. direct reaction with oxygen

what are the four mechanisms of biological redox reactions?

the standard hydrogen electrode (0 V)

what is the reference point for all reduction potentials?

Subtract the donor’s E’° value from the acceptor’s E’° value.

How is ΔE’° calculated?

The real concentrations of the donor and acceptor species

What determines the actual (nonstandard) ΔE of a reaction?

ΔE = ΔE’° + (RT/nF) ln([A][B]/[C][D])

What is the equation for ΔE in the reaction A + B → C + D?

A soluble 2-electron carrier that transfers electrons as a hydride

what type of electron carrier is NADH?

They are 1- or 2-electron carriers involved in hydride and direct electron transfers

What roles do FAD and FMN play in redox?

no, they usually remain tightly bound to their enzymes

Are FAD and FMN free in solution like NADH