Topic 8 Flashcards
2 purposes of Catabolic pathways
breakdown of larger molecules, release and storage of high energy molecules,
catabolic pathways are
oxidative, cofactors are reduced
Oxidative phosphorylation
1) oxidation of reduced cofactors and reduction of molecular oxygen
2) phosphorylation of ADP to ATP
how are the 2 processes of oxidative phosphorylation linked
proton gradient across mitochondrial membrane
overview of oxidative phosphorylation
reduced cofactors in glycolosis and CAC, ETC, proton gradient, ATP
where does this occur
mitochondrial membrane
Complexes 1-4 are
integral membrane proteins
coenzyme Q
lipid soluble coenzyme, hydrophobic, transports to Complex iii from i and ii, ubiquinol
cytochrome C
peripheral membrane protein
electrons move from ______ reduction potential
lower to higher
Flavin mononucleotide
FMN + 2H+ 2e- FMNH2
Iron-sulfur clusters
Fe3+ + e- Fe2+
Cytochrome heme group vs hemoglobin heme group
cytochrome prosthetic group does not have proximal histidine that prevents oxidation of Fe, cuz you want it to oxidize
higher reduction potential
more neg G
terminal electron acceptor
O2
what kind of transport uses redox reactions to transport protons across membrane
primary transport
1 NADH equals how many protons
10
when reductional potential increases (more positive) free energy
decreases
Complex II is what and purpose
succinate dehydrogenase, contains FAD as prosthetic group, oxidizes succinate to fumerate (CAC) , e- moved to coenzyme Q, no protons
1 FADH2 how many protons
6
Proton gradient
matrix has high pH (neg) and intermembrane space has low pH (pos)
potential energy converted to
chemical energy in phosphoanhydride bonds in ATP
how many H per ATP
3
How many ATP per NADH
~3.3
ATP synthase
Fo - oligomycin, transmembrane portion, protons pass through, triggers change in F1
F1- catalytic portion, synthesis of ATP from ADP and Pi
what does rate of ATP synthesis affect
proton movement and oxygen consumption
every turn of central shaft makes how many ATP
3
rate of oxygen consumption is coupled to
ATP synthesis
P:O ratio
amount of ATP per oxygen atom reduced to water
how much water is made per electron carrier
1 (each 2e-)
P:O ratio NADH reoxidized
~2.5
P:O ratio FADH2 reoxidized
~1.5
rate of oxidative phosphorylation depends on
Concentration of ADP
oxygen consumption increases when
concentration of ADP increases
what does ADP concentration reflect
energy consumption of cell
coupling in low and high energy use
KNOW THE PATHWAY and CHART
uncoupled protons
enter without going through ATP synthase, generate heat instead (Ek)
do mammals use uncoupled deliberately
yes to purposely generate heat
in the presence of an uncoupler, O2 ….
consumption increases
what happens in the presence of an uncoupler
electron transport occurs without ATP synthesis, and catabolism of fuel molecules occurs without ATP synthesis
-proton gradient dissipated faster
what happens when proton gradient is dissipated faster
rate of e- transport goes up therfore O2 consumption rises, rate of reaction in citric cycles rises
example of uncoupler
2,4-dinitrophenol “diet pill” essentially burns fat without activity
