Unit 2 - ETC Flashcards
Summary of glycolysis, pyruvate oxidation and krebs products
1) - 2 ATP - 2 NADH
2) - 2NADH
3) - 2 ATP - 6NADH - 2FADH
we need to use our energy carriers to make 34 ATP using the ETC and oxidative phosphorylation
ETC and Oxidative phosphorylation
- inner mitochondrial membrane
- 2 e- from NADH and FADH2 passed down a chain of oxidizing agents to O2 making water as its waste
ETC
in the presence of O2, a series of mostly transport proteins built into the inner membrane is used to link electron transports to ATP synthesis
ETC arranged how?
order of increasing electronegativity
ETC carries NADH and FADH2
NADH is oxidized at NADH dehydrogenase releasing 2e-
FADH2 is oxidized at succinate dehydrogenase releasing 2e-
Electrons flow downhill
electrons move in steps from carrier to carrier downhill to O2
- each carrier is more electronegative
Reactions in ETC
a series of REDOX reactions occur between each protein complex to transfer the electrons
- two e- transferred each time
- as e- move down the ETC energy is released and the e- bc more stable
at the end of ETC
the electrons have to reduce something! oxygen
Oxygen is reduced as it picks up 2e- and 2 protons
matrix is less acidic than the intermembrane space
ETC 4 proteins complexes
- NADH dehydrogenase complex 1
- succinate dehydrogenase, complex 2
- cytochrome c reductase, complex 3
- cytochrome c oxidase, complex 4
ETC 2 electron shuttles
- ubiquinone (Q or UQ)
- cytochrome c (cyt c)
Oxidative Phosphorylation protein complex(two)
- ubiquinone
- cytochrome c
1) path of electrons: NADH
2 electrons r dropped off by energy carriers: NADH drops e- off at complex 1, forms NAD+, complex 1 pumps protons (H+) across the inner membrane to the intermembrane space
2) path of electrons: FADH2
FADH2 drops e- off at complex 2 forms FAD
- Ubiquinone
UB shuttles the e- from complex 1 and 2 to complex 3, which pumps protons (H+) across the inner membrane to the intermembrane space
- Cytochrome C
e- pass from complex 3 to cytochrome c, another electron shuttle
- Complex 4
cytochrome c shuttles the e- to complex 4. which pumps protons (H+) across the inner membrane to the intermembrane space
- complex 4
electrons from complex 4 combine w an oxygen atom in the matrix and 2 H+ ions to make water
Pumping protons
- as electrons pass through the complexes they release some energy
- complex 1, 3, 4 use this energy to pump )H+) across the inner membrane to intermembrane space
- complex 2 and electron shuttles do NOT pump protons
Oxidative Phosphorylation
as protons r pumped into the accumulate in the intermembrane space, a gradient forms:
- Chemical component
- Electrical Potential Component
Chemical Component
higher concentration in intermembrane space
electrical potential component
(PMF)
+ charges repel each other and r attracted to the - interior of matrix
form the Proton-Motive-Force (PMF)
Proton Motive Force
a force that moves protons bc of a electrochemical gradient of protons across a membrane
Intermembrane Space
is impermeable to protons which enables them to accumulate in the intermembrane space. To re-enter the matrix the protons must be pumped through the protein channel ATO synthase
ATP synthase
has a channel that allows protons to move down their gradient and cross the inner membrane to the matrix = chemiosmosis
Chemiosmosis
provides enough energy to make ATP from ADP + Pi
Oxidative Phosphorylation
unlike substrate level phosphorylation, this involves a free Pi. a phosphate does not jump from another compound
end of this
for every H+ proton through ATO synthase channel 1 ATP if formed
DADH yields
3ATP so 10NADH x 3ATP = 30
FADH2 yields
2ATP so 2FADH2 x 2ATP = 4
Total ATP made via oxidative phosphorylation
34
(38 atp r made from the oxidation of 1 glucose)
