ETC Flashcards
T or F: ETC can only occur in cells with mitochondria
T
Name the 4 complexes
Complex I (NADH dehydrogenase), Complex II (Succinate Dehydrogenase), Complex III (Ubiquinone-Cytochrome C oxidoreductae), Complex IV (Cytochrome oxidase)
Which membrane of the mitochondria is more permeable?
Outer membrane. Inner membrane is much more tightly regulated
Where does NADH feed into the ETC?
Complex I (NADH dehydrogenase)
Where does FADH2 feed into the ETC?
Complex II (Succinate dehydrogenase)
Trace an electron from NADH2 through the ETC
Complex I to Complex III via Ubiquinone to Cytochrome C to Complex IV, to Oxygen
What is the redox potential? how does it relate to ETC?
The more negative the redox potential the greater the tendency to lose electrons
What is the redox potential of Complex I? Complex IV?
-0.32, +0.82
NADH donates electrons to Complex I via?
FMN to FMNH2 (sulfur center to accept the Hydride and proton from NADH)
NADH donates electrons via? FADH2 donates electrons via?
Hydride ion and proton, 2 hydrogens
FADH2 donates electrons via complex II how?
Directly to CoQ
FMNH2 is located where and how is it formed? Donates to what?
From NADH2 in the Complex I. Donates to CoQ
CoQ is reduced to?
CoQH2
What happens to CoQH2?
Donates to Iron in Complex III (cytochrome bc1)
T or F: There are pathways for FADH2 to feed into CoQ without using Complex II
T
Complex III accepts electrons from CoQH2 by?
Reducing Fe+3 to Fe+2
Complex III donates to…?
Cytochrome C via the reduction of Fe+3 to Fe+2
Cyto c donates to?
Complex IV via iron
Complex IV donates to?
Oxygen (half mole of diatomic oxygen)
Complexes I, III, and IV do what?
Using electron donated pump hydrogen from matrix to intermembrane space
Which is more acidic: Matrix or intermembrane space?
Intermembrane space
What is Complex V also known as?
ATP synthase
What is the function of Complex V?
Allows protons to move from IM to MM and in doing so oxidatively phosphorylates ADP and P into ATP.
How does ATP/ADP transport across inner membrane of mitochondria?
ATP/ADP co-transport that allows ATP into the IM from MM and ADP from the IM into the MM
What are the two domains of ATP synthase?
F0 and F1
Amytal rotenone blocks what step of ETC?
Sucicinate Dehydrogenase (electrons to CoQ)
Antimycin A blocks what in the ETC?
Cyto bc1 exchange with Cyto c
Cyanide, carbon monoxide, and sodium azide block what?
The transfer of electrons from Complex IV to Oxygen
What are uncoupling proteins?
Proteins that create proton leaks allowing protons to move from MM to IM without capturing energy as ATP
What is the function of Glycerol phosphate shuttle?
DHAP is made into Glycerol 3-phosphate via oxidation of NADH. Glycerol 3-phosphate moves from cytosol to IM. Glycerol 3-phosphate can then reduce FAD to FADH2 which then can donate directly to CoQ
Glycerol Phosphate shuttle: What is DHAP made into in the cytosol? How?
DHAP to Glycerol 3-phosphate via Cystolic glycerophosphate dehydrogenase and consuming NADH and H+
Glycerol Phosphate Shuttle: In the IM what is glycerol 3-phosphate made into?
DHAP vis Mitochondrial glycerophosphate dehydrogenase and making FADH2
T or F: The Glycerol Phosphate shuttle effectively costs 1 ATP from intermediates
T
What is the function of Malate aspartate shuttle?
Transport NADH equivalents across the membrane
MA shuttle: Oxaloacetate is made into?
Malate via cytosolic malate dehydrogenase consuming a NADH and H+
MA Shuttle: What happens to cytosolic malate?
Crosses into MM, and is made into oxaloacetate producing NADH and H+ via mitochondrial malate dehydrogenase
Glycerol phosphate shuttled products feed into where in the ETC?
CoQ stage
Malate aspartate shuttled products feed into where in the ETC?
Complex I (NADH dehydrogenase)
What happens to oxaloacetate in the MM for MA shuttle?
Combines with glutamate and via amino-transferase is made into either aspartate or alpha ketoglutarate
What is transported back into the cytosol from the matrix in MA shuttle?
Aspartate and Alpha-ketoglutarate which then via amino-transferase is made back into glutamate and oxaloacetate
T or F: In the MA shuttle, glutamate is transported from the cytosol into the MM
T; combines with oxaloacetate to get back across into cytosol
NADH at complex I gives how many ATP?
3
NADH that is transported via the GP shuttle gives us how many ATP?
2
Each FADH2 gives us how many ATP?
2
What is the general function of shuttle processes?
Shuttle reducing equivalents from NADH generated in glycolysis from the cytosol to the mitochondria
How much more ATP is generated from glycolysis products if MA is used instead of GP shuttle?
2 ATP
How many ATP are formed via the complete oxidation of one Acetyl-CoA?
12 ATP
What are three types of ROS
Hydroxyl radical, superoxide, and hydrogen peroxide
What is the function of superoxide dismutase?
Takes 2 superoxides to Hydrogen peroxide
What is the function of catalase?
Breaks down hydrogen peroxide into water and oxygen
What happens to hydrogen peroxide in the presence of iron?
Made into hydroxyl radical
How is hydrogen peroxide made into JUST water?
Glutathione peroxidase
Describe the cycle of glutathione peroxidase/reductase
H2O2 to Water by glutathione peroxidase takes 2GSH to GSSG. GSSG is reduced to 2 GSH by glutathione reductase producing NADP+ from NADPH+
Describe the structure of G-SH
Glutamate attached to cysteine attached to glycerine
What makes NADPH for the glutathione pathway of H2O2 destruction?
Pentose phosphate pathway
GSSG is _______ to 2G-SH by _______
reduced; Glutathione reductase
2 G-SH is _______ to G-S-S-G by _______
oxidized; Glutatione peroxidase
Which step int he glutathione process degrades H2O2?
Oxidizing of 2 G-SH to G-S-S-G by Glutathione peroxidase
Glutathione reductase is accompanied by what rx?
NADPH + H to NADP+
