Bio - ETC and chemiosmosis

Where is NADH and FADH2 used

ETC

Where does ETC and chemiosmosis take place

Inner membrane of mitochondria

Cristae

Folds of inner membrane

Complex 1

NADH dehydrogenase
Takes e- from NADH
Breaks NADH into NAD+ and H+
Pumps H+ across inner membrane

Complex 2

Succinate dehydrogenase
Takes e- from FADH2
Does not pump H+

Why does FADH2 make less ATP than NADH

FADH2 enters ETC at a lower energy point so it drives less H+ pumping

Complex 3

Cytochrome complex
Takes e- from Q (ubiquinone)
Passes e- to cytochrome C
Pumps H+

Complex 4

cytochrome oxidase
Takes e- from cytochrome C - passes to O2
Pumps H+
Oxygen needed for this step to oxidize complex 4

What energy is used to transport H+

Each time e- are transfered, energy is released

How much ATP does NADH and FADH make

NADH - 2.5 ATP
FADH2 - 1.5 ATP

What moves H+ to matrix

As H+ concentration increases, electrochemical gradient pushes them back into matrix

ATP synthase

Structure that is adjacent to e- carriers
Enzyme and membrane channel
Allows H+ to diffuse through
Flow of e- creates kinetic energy to combine ADP and Pi to form ATP

Ubiquinone (Q)

Mobile e- carrier
Picks up e- from complex 1 and 2
Delivers e- to complex 3
shuttle molecule
Inside membrane
bridge between steps

Cytochrome C

Carriers e- from complex 3-4
Shuttle molecule
Moves freely along inner mitochondrial membrane

Why is oxygen so important

Takes e- from complex 4 and 2 H+ to make H2O
Availability of O2 usually limits our ability to make ATP

G3P shuttle

Transfers e- from NADH from glycolysis to mitochondria
e- transfered to DHAP to form G3P
G3P travels through outer mitochondrial membrane
G3P passes e- to FAD to make FADH2

Malate aspartate shuttle

Used by cardiac and liver and kidney
e- from NADH go to oxaloacetate to form malate
Malate travels through outer membrane, releases NADH and goes back to oxaloacetate
Oxaloacetate is turned to aspartate to return to cytosol
Heart and liver need efficient ATP production, so it uses this
Only if NADH concentration is more in cytosol than inside

Why does NADH make more ATP than FADH2

FADH2 enters ETC at a lower energy point so it drives less H+ pumping