Lecture 3B Flashcards
(54 cards)
low-potential electron donors (are more _______________)
Electronegative
what happens to low-potential electron donors?
Oxidized
where are the resulting electrons driven through?
Electron transport chain
How is proton motive force (PMF) arise?
Due to movement of electrons
the terminal electron acceptor in Aerobic respirations
Oxygen
How is fermentations different from aerobic respirations
Fermentation: do not require external electron acceptors, generates ATP through subtrate-level phosphorylation
Aerobic respirations: can generate ATP through ETC
mV value of NADH/NAD+
−320 mV
mV value of FADH2/FAD, Em,7
+31 Mv
mV value of
HCO2−/CO2, Em,7 =
−420 mV
mV value of
succinate/fumarate, Em,7 =
+31 mV
mV value of
H2/H+, Em,7 =
−420 mV
mV value of
O2/H2O, Em,7 =
+815 mV
mV value of
NO/N2O, Em,7 =
+1,300 mV
small organic compounds that can donate electrons
Formate and succinate
In Aerobic bac. ETC;
redox spans gives rise to a thermodynamic driving force of more than
1eV
In Aerobic bac. ETC; Each proton transport across the membrane has a thermodynamic cost of around
4.6 Kcal mol^-1
In Aerobic bac. ETC;
with an ~1-V redox span between the initial donor and acceptor, how many protons are pumped for each electron transferred?
Five protons
Why is stepwise drop in potential along the respiratory chain imporant?
It allows for energy conservation rather than dissepated as heat.
also forms an integral part of the proton-motive respiratory machinery
Cell membrane
How does cell membrane forms a important machinery in PMF?
- Provides an isolating layer
- Lipid hydrocarbons establishe proton conduction pathways, and proton uptake
Lipid composition of bacterial cell wall
- zwitterionic
- anionic
- highly glyosylated lipids
a lipid that is 75% in E. coli
Phosphatidylethanolamine
a lipid that is 20% in E. coli
Phosphatidylglycerol
