Lecture 14 - Bioenergetics 2 Flashcards
Coupled Reactions
It needs:
- common intermediate
- mechanism for energy transfer to occur
To find overall triangleG combine triangeG’s of the two reactions
ATP
Free energy charge for ATP hydrolysis large and negative because:
- terminal anhydride bonds easily broken
- electrostatic repulsion among four neg charges
Hydrolysis of ATP has high activation energy
Transfer of Energy
Potential energy in nutrient molecules Chemical transformations ATP Chemical transformations Energy for charge
Transfer of Energy by Transfer of Electrons
Electrons are transferred from one or more redox reactions in cell to specific electron carriers
Electron carriers then transfer electrons to other redox reactions and electron carriers in their inner mitochondrial membrane
Ways that Electrons are transferred?
Through a series of redox reactions in a cell
By specific carriers
- carry electrons from a redox reaction in one location to redox reaction in another
- NAD, FAD
Oxidising and Reducing agents
Oxidising - molecule that accepts electrons
Reducing - molecule that donates electrons
Electron Carriers
NAD and NADP - water soluble - transfer two electrons as a hydride ion FMN and FAD - strongly bound to proteins - can transfer one or two electrons
Reduction Potentials
A way of tracking the number of e- stored or transferred
Use the Nernst Equation
Oxidation and Reduction of Carbon
Carbon reduced if:
- number of H atoms increases
- number of bonds to more electronegative atoms decreases (O, N, F)
Carbon oxidised if:
- number of H atoms decreases
- number of bonds to more electronegative atoms increases
Estimating Energy content of molecules
Energy from breaking C-C to C-H = -220kJ/mol
What are reducing bonds?
Any C-C, C-H, C-N, N-H bond
When these bonds are broken, electrons are released and the carbon is oxidised
