ETC Flashcards
What is the outer mito membrane composed of? Is it permeable?
50% lipid and 50% protein; yes pretty much
Inner mito membrane components? Permeable or impermeable?
80% protein/ 20 % lipid
impermeable
What can you find in the mito matrix? (3 things)
enzymes of the CAC; the PDH complex, and enzymes for B-oxidation
THE ETC is a series or chain of electron carriers in the inner mito membrane which funnels electrons from what to what?
reduced substrates such as NADH and succinate to oxygen
What is the process of coupling oxidative metabolic substrates by the ETC to the phosphorylation of ADP to form ATP
oxidative phosphorylatin
What are the 2 types of electron carriers involved in the ETC?
- Proteins: dehydrogenases and iron-containing proteins, non-heme iron proteins
- Lipids: CoQ
What are 3 examples of reducing equivalents?
- naked electrons
- H atoms
hydride ions
What are the 4 major DHs? What do they use?
- Succinate DH (FAD)
- NADH dehydrogenase (FMN)
- Fatty acyl-CoA DH (FAD)
- Glycerol-3-Phos DH (FAD)
What are the 2 types of iron-containing proteins?
- cytochromes: heme-iron: Fe2+ (reduced form)
2. Non-heme iron: Fe-S: Fe2+ reduced
What is the only non-iron electron carrier in the ETC?
coenzyme Q (ubiquinone)
What are the 4 ETC enzyme complexes?
- NADH-Coq Reductase:
NADH + H+ CoQ –> NAD+ CoQH2 - Succinate-CoQ Reductase
Succinate + CoQ –> Fumarate + CoQH2 - CoQH2-Cytochrome c Reductase
CoQH2 + 2 cyc c (Fe3+) –> CoQ + 2 cyc c (Fe2+) - Cytochrome Oxidase
4 cyc c (Fe2+) + 4H + O2 –> 4 cyc c (Fe3+) + 2H2O
What are inhibitors of complex IV?
cyanide, CO
Complex IV also contains what ion?
Cu.. fluctuates between CU2+ and Cu3+
Where is the electrochemical gradient established in the ETC?
in the periplasmic space; generated by Com 1, 3, 4
Describe the two subunits of ATP synthase?
F0: transmembrane proton channel
F1: makes ATP from ADP
What are 2 uncouplers of the ETC?
DNP: inhibits formation of ATP but allows electron transport and proton pumping to still occur
Brown Fat:
How does ATP actually get into the cytosol?
adenine nucleotide translocase, which exchanges ATP for ADP
What is Atractyloside?
a specific inhibitor of adenine nucleotide translocase
What can inhibit transport of ATP into the cytosol?
atractyloside
How does MERFF result?
point mutation in the mitochondrial gene for lysine tRNA; cytochrome oxidase activity is diminished
What results when there is a mutation causing a problem with cytochrome oxidase activity?
MERFF
What is MELAS?
point mutation in leucine tRNA; cytochrome oxidase activity is near normal
What is the difference between MERFF and MELAS?
cytochrome oxidase activity is reduced in MERFF, but cyc oxidase activity is basically normal in MELAS
Poisoning by herbacides?
DNP: leads to hyperthermia due to uncoupling of oxidative phosphorylation witha resultant increase in heat production
treat with ice baths, oxygen, electrolytes
