ETC Flashcards
1
Q
ETC overview
A
- energy rich molecules are metabolized by series of oxidation reactions yielding CO2 and H2O
- oxidation reactions are coupled to the transfer or electrons(reduction) to the electron carriers FAD and NAD+(oxidation)
- carriers donate electron to ETC and lose free eneegy
- electron is coupled with proton to create gradient
- flow of protons drives ATP synthase
2
Q
RedOx chemical reactions
A
-represent transfer of H atoms (1 proton and 1 electron)
3
Q
Mitochondria outer membrane
A
-permeable to most ions and small molecules
4
Q
Mitochondria inner membrane
A
-impermeable to most small ions and small and large molecules
5
Q
Mitochondrial matrix
A
- TCA cycle enzymes (except complex 2)
- fatty acid oxidation enzymes
- mtDNA and mtRNA (circular and encode for some things involved in ETC)
- mitochondrial ribosomes
- ETC takes place here
6
Q
protein complexes
A
- embedded in the inner membrane and span the WHOLE membrane.
- complexes 1-4 are part of the electron transprt
- complex 5 is the enzyme ATP-synthase
- CoQ is the only nonprotein carrier (hydrophobic and can freely move around the membrane)
7
Q
Complex 1
A
- NADH dehydrogenase
- accepts electron from NADH generated during glycolysis, pyruvate decarboxylation, and TCA cycle
- contains FMN that accepts 2 hydrogen atoms
- contains iron sulfur center required for next step
8
Q
Complex 2
A
- succinate dehydrogenase
- ONLY ONE embedded in inner mitochondrial membrane
- FAD contains iron sulfur center
- FADH2 generated are directly transferred to CoQ and skip complex 1
9
Q
Coenzyme Q
A
- only non protein carrier
- quinine derivative with long hydrophobic tail so it can freely move along membrane
- accepts the electron from complex 1 and 2 and pass them to complex 3
10
Q
Cytochrome proteins
A
- CYT
- Cyt b and c1=complex 3
- Cyt a and a3=complex 4
- Cyt c freely moves in intermembrane space because soluble
- each contain heme group
- Cyt iron is reversibly converted from ferric(Fe3+) to ferrous(Fe2+)
11
Q
Complex 4
A
- Cyt a and a3 or c oxidase
- contains copper required for electron transfer
- the only complex that contains heme iron group that directly interacts with O2
- electron moves from CuA to Cyta3 associated with Cub to O2
- oxygen is last acceptor because it is the strongest
12
Q
Strongest donor and acceptor
A
- NADH is strongest donor
- O2 is strongest acceptor so held for last so you can continue to transfer electrons down the chain
13
Q
Chemiosmotic hypothesis
A
- as electrons go through 1,3,4, the reaction is coupled with pumping of protons across inner mitochondrial membrane to intermembrane space
- creates electrical and pH gradient(outside is more positive)
- gradient drives ATP synthesis
- gradient serves as common intermediate that couples oxidation to phosphorylation
14
Q
Complex 5
A
- ATP-Synthase
- multisubunit enzyme
- domain F0-spans mitochondrial membrane
- domain F1- is extramembranous(in mitochondrial matrix)(head spear is in matrix)
15
Q
ATP-Synthase Function
A
- protons flow back through F0 domain driven by the gradient
- F1 domain rotates
- F1 goes through conformational changes that allow ATP+P to bind and phosphorylate ADP—>ADP, and release ATP
16
Q
Inhibition of ETC
A
- prevent the flow of electrons
- results in NADH build up
- build up inhibits TCA cycle and causes pyruvate to go to lactate
- serum lactate levels elevate
- highly aerobic tissues are effected(heart and brain)
-any inhibition will stop the whole damn thing
