what are the two half reactions of NADH oxidation?
what is the overall full reaction?
what is the delta E and delta G for this reaction? what does this energy drive?
a. 1/2O2 + 2 H+ + 2e- --> H20
b. NAD+ + H+ + 2e----> NADH
NADH + H+ + 1/2O2<-> H20 + NAD+
G=-52.6 E=1.14....drives electron transport and proton pumping
what is the chemiosmotic hypothesis?
electron transport through respiratory chain leads to pumping of protons from matrix to cytoplasmic side of inner mitochondrial membrane...pH gradient and membrane potential constitute a proton-motive force that is used to drive ATP synthesis
TYPICALLY, what is the change in pH between the cytosol and matrix (cytosol-matrix)
-1.4....matrix will have higher pH than intermembrane space
how did we prove the proton motive force idea?
bacteriorhodopsin was incorporated into a synthetic vesicle, it pumped protons upon shining light, generating the PMF....then mitochondrial atpase was incorporated into the vesicle and it was shown that ATP was synthesized, proving the theory
what summed together equals the work done against the proton motive force (deltaP)
work against pH gradient (deltapH) and work against charge gradient (deltapsi)
what is the equation for deltaG when a proton moves from the matrix to the cytosol (against the proton motive force)?
what is deltaP equation?
-2.303 RT deltapH + nFdeltapsi
-.062deltapH + deltapsi
what is the typical deltaP and delta G or the ETC?
what does this mean?
deltaG= 5.2 kcal/mol
proton getting pumped from matrix to cytosolic side will create an increase in gibbs free energy, thus the oppositte direction will result in a negative gibbs free energy allowing it to be a spontaneous reaction and producing ATP
what is Faraday's constant?
what 2 MAIN components make up ATP synthase? which one is found in the inner membrane?
Fo and F1....Fo is imbedded in inner membrane, F1 is in the matrix
how many subunits make up the Fo subunit of ATP synthase and what does each subunit do?
a: proton channel
c: ring of 10-14 c that rotates gamma subunit
b: holds Fo and F1 together
what subunits make up F1 in ATP synthase?
what does each do?
alpha, beta, gamma, delta, epsilon
alphabeta ring: hexamer, catalytic unit, attached to b (from Fo) via delta
gamma: breaks symmetry in alphabeta ring
what is the rotor part of ATP synthase?
what is the stator part of ATP synthase?
c-ring and gammaepsilon stalk
a, b, delta, and alphabeta
what important amino acid residue is found in subunit c of Fo ATP synthase?
what does it act as?
what is important about the structure of subunit a in Fo?
thought to have 2 channels (one leads to matrix and one leads to cytosolic) for protons that leads to the Asp...on cytosolic side, aspartate takes a proton while on matrix side, aspartate releases a proton
how does the c-ring rotate?
proton enters from intermembrane space into cytoplasmic half channel to neutralize aspartic acid charge in c subunit.....with neutralized charge, c ring can rotate clockwise by 1 c subunit, moving an aspartic acid residue out of the membrane into the matrix half channel, this proton can move into the matrix
how many protons can enter the matrix side via the C ring via 1 full revolution?
the rotation of the C ring will power the rotation of the _____
gamma subunit in F1
which subunits of F1 do not participate in any reactions and what is bound to them?
the three states can the beta subunits of F1 be found in?
What happens in each of the three states?
what is the shift of the subunits (what precedes what?)
open, loose, or tense
O: open, binding and release of ATP/ ADP and phosphate can occur
L: loose, ADP and phosphate are bound and trapped
T: ATP can be made from ADP and phosphate
when viewed from below, which way will the asymmetric gamma subunit rotate?
each 360 degree rotation of the gamma subunit will lead to synthesis and release of _________
1 molecule of ATP from EACH subunit (3 ATPs are made total)
how many protons are required for 360degree rotation of C-ring?
how many ATPs are synthesized per full rotation of C ring?
thus how many protons are required to make 1 ATP?
what is the function of the ATP/ADP translocase?
what other carrier is coupled to this translocase?
what inhibits the ATP/ADP translocase and how?
shuttles ATP out of the mitochondria and brings ADP in.....negative ATP gets shuttle out of mitochondria and 1 H+ comes in with ADP via phosphate carrier (H+ and phosphate both get shuttled into the matrix)
atractyloside (binds when open to cytoplasmic side) and bongkrekic acid (binds when open to matrix side)
how many protons are needed to make one ATP available in the cytoplasm?
4 (3 to spin and 1 to move the ATP)
what is the P/O ratio?
--number of phosphate consumed per oxygen atom in the ATP synthesis by mitochondria (ATP produced to O2 used)
number of ATP synthesized upon oxidation of one NADH or FADH2
how many cytosolic ATPs are produced per oxidation of 1 matrix NADH?
10/4 means about 2.5
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