Lecture 33 Flashcards
describe mitochondrion
cristae = invaginations of inner membrane
respiratory chain in membrane
inner membrane, matrix and outer membrane
describe op - numbers
nadh = 2.5 atps
fadh = 1.5 atps - doesnt touch complex 1, only 3 = 6 protons so less atp
proton: oxygen = 10:1
describe op - gen
nadh - 2e- oxidized to nad+
4 protons
e- passthrough complex 1, coq, complex 3, cyt c, 4 protons - complex 4 2 protons - complex 5
10 protons pumped total = make one h2o molecule
1,2,3,4 = etc
conformational change = protons pumped from matrix - inner most compartment of mito into inner membrane space
protons pass through complexes 1,3,4 not 2
what establishes proton gradients
membranes
what are proton gradients
sources of enrgy
electrochem
150-200mv across membrane in mito
30mv/meter since small membrane
describe reaction of Free Energy change of NADH to O2
NADH+H + O –→NAD +H O=-220kJ/mol
-0.32 v = low standard reduction potential - neg = wanna give away
therefore electrons flow from low–> high reduction potential
describe oxphos wars
hypothesis = atp synthesized from high energy intermediate of respiratory chain during oxidation
akin to = glyceraldehyde 3 phosphate dehydrogenase (GAPDH) where phosphorylation coupled to oxidation
no intermediate
diseq of protons drives it
what is similar to gapdh
chemical coupling hypothesis
describe evidence of chemi osmotic coupling = 6 statements
- The respiratory chain can function in the absence of phosphate- not a phosphate intermediate
- The # moles of ATP generated through NADH oxidation was not an integer - half an intermediate does not work
- An intact IMM is required for OXPHOS - need to pump protons
- Key electron transport proteins span the IMM
- Uncouplers such as 2,4-Dinitrophenol (DNP) inhibit ATP synthesis - dissipates membrane potential - no atp
- Generating an ARTIFICIAL proton gradient permits ATP synthesis without electron transport - artificially drive atp just by protons
Why so many redox reactions?
needs to harness energy
40-50% rest lost to heat
describe p/o ratio - stoich of oxphos - gen
atp synthase - 13 protons
motor generates atp
push subunit ring - turns
h= from inter-membrane space to mito
each 360 rotation generates 3 atps
8 subunits = 8 protons go through for every 360 turn
what p/o ratios through complex 1 and 2
P/O ratio through Complex I: 10/3.7 = ~2.5
P/O ratio through Complex II: 6/3.7 = ~1.5
missing 4 protons from complex 1
describe how o/p ratio made - whole story
p/o = amount of atp molecules produced from every oxygen consumed
10h+ from complex 1, 10/3.7 = oxygen to proton stoich
8 protons - 3 atps made = 8/3 = 2.7 p/atp
inorganic phosphate comes from outside via transporter = symporter and brings in 1 proton with phosphate
Proton to atp stoich = 3.7
11/3 = 3.7
2e- = 10 protons
Aerobic Metabolism Balance Sheet - cytosol glycolysis
from on glucose
2 atp net
2nadh (x2.5atp/nadh) = 5
total = 7 atps
Aerobic Metabolism Balance Sheet - mito pyruvate dehydrogenase (pdc)
From one pyruvate
1 nadh (x2.5/nadh) = 2.5 atp
total = 2.5 atp
MUST DOUBLE SINCE 2 PYRUVATE
