Oxidative Phosphorylation Flashcards
(35 cards)
what makes proton gradient so powerful?
concentration and voltage gradient both in same direction
what is ATP synths?
synthesizes ATP from ADP and Pi
what are the two portions of the ATP Synthase?
Membrane portion (Fo)
matrix portion (F1)
what does the membrane portion do?
translocates H+
what does the matrix portion do?
synthesizes ATP
what is the effect of proton binding to Fo?
drives rotation of the “c” subunits, which makes γ rotate, which stimulates conformational changes in the F1 β subunits, making ATP.
where is the F1 head piece located? what about the F0 pore?
matrix, composed of 6 subunits, alternating alpha and beta subunits, 1 pair is an alpha and beta so a total of three catalytic sites;
inner mitochondrial membrane
what causes the conformational change of the ATP synthase?
the movement of protons into the FO portion of the ATP synthase, it causes a turret like motion which is connected by a stalk like portion or a gamma/epsilon subunit
what are the sites located in the F1 head group? Does the headgroup move? how does the binding change mechanism work?
Three sites: one is empty, one contains ADP + Pi,
one contains ATP
no
energy favorable for the making of ATP, energy is needed to remove the ATP from its active site and this happens due to the turning of the gamma subunit while also forming ATP from ADP and Pi, empty site becomes loaded
what is proton motive force due to?
membrane potential and proton concentration gradient
What is the purpose of setting up the H+ gradient?
its set up by the proton gradient that drives ATP synthesis by ATP synthase phosphorylating ADP to ATP
what is needed to ensure the proper functioning of the ETC?
1) all the components of ETC to create the proton gradient
2) ATP synthase to synthesize ATP
3) Oxygen – terminal acceptor of e- so that electrons can move through ETC
4) Reducing coenzymes (NADH and FADH2) to provide electrons
5) intact inner mitochondrial membrane for the H+ gradient.
ATP synthesis is dependent on?which requires ____ as an electron source?
ETC; NADH/FADH2
what does the formation of the proton gradient promote?
ATP synthesis
during ATP synthesis, this requires O2 reduction to H2O T/F?
True
why is proton transport through the ATP synthase important?
ATP synthesis is dependent on this
in ATP synthesis, what happens to ADP?
its phosphorylated to ATP
what are the effects when ATP synthesis controls the rate of ETC O2 consumption?
it decreases supply of NADH/FADH2
stimulates ETC to regenerate the H+ gradient
increases the rate of O2 consumption
depletes the inter membrane space of H+
ADP conversion to ATP
where does NADH come from?
TCA, Glycolysis, Fatty acid oxidation
what is ATP-ADP translocase?
Ensures steady supply of ADP for ATP synthase. Flow down their concentration gradients
Requires energy equivalent of one H+
H+ gradient drives Pi into matrix for synthase: 1 to 1 ratio
the outer membrane is a voltage or chemical gradient?
voltage gradient
why does ATP synthesis require an intact inner mitochondrial membrane with an H+ gradient?
The ETC makes the proton gradient. The ATP Synthase uses the gradient’s energy.
The ATP Synthase is the major pathway for H+ reentry into the matrix.
Any agent that allows H+ to pass into the matrix will “uncouple” the ETC (which generates H+ gradient) from ATP synthesis (which uses the H+ gradient) so ETC will continue but ATP production is affected and this is called uncoupling
what is the effect of a minor H+ leak versus a major H+ leak?
Only a little H+ leak? Proton gradient sufficient to drive ATP, just slower.
Major H+ leak? Proton gradient not sufficient to support ATP synthesis at needed level.
what is brown fat?
helps keep the body warm like babies and used to generate heat for baby
