Mitochondria and Oxidative Phosphorylation Flashcards
(24 cards)
How many ATP does one NADH produce in the ETC?
3
How many ATP does one FADH2 produce in the ETC?
2
How are mitochondria inherited?
Maternally
What are 5 pieces of evidence supporting the endosymbiosis theory?
Mitochondria only arise from preexisting mitochondria.
Mitochondria have their own genome which resembles prokaryotes.
Mitochondria have their own protein synthesising machinery which resembles prokaryotes.
The first amino acid of their transcripts is fMet which is the same as in bacteria.
A number of antibiotics bock protein synthesis in mitochondria.
What is the route for electrons in the ETC?
NADH dehydrogenase complex –> ubiquinone/coenzyme Q –> cytochrome bc1 complex –> cytochrome C –> cytochrome oxidase –> oxygen
What allows the flow of the electrons in a logical order?
The fact that each unit in the chain has a higher affinity for electrons/has a higher redox potential (more positive)
What is the redox potential?
The ability of a redox couple to accept or donate electrons.
What does a negative redox potential suggest?
An ability to donate
What does a positive redox potential suggest?
Ability to accept
Which is the membrane bound part and which projects into the mitochondrial space of ATP synthase, F0 or F1?
F0 - membrane bound, F1 - projects.
Which subunit acts as an axle in F1?
Gamma
Which subunit undergoes structural changes due to gamma axle rotating?
Beta
Why does FADH2 make less ATP?
Because it passes its electrons directly to ubiquinone
Name 5 metabolic poisons
Cyanide, carbon monoxide, malonate, oligomycin and dinitrophenol
Explain the mechanism of cyanide
Binds with high affinity to the ferric (Fe3+) form of the ferric group of cytochrome oxidase and inhibits it, blocking the flow of electrons
Explain the mechanism of carbon monoxide
Binds to haemoglobin stronger than oxygen so oxygen is not supplied to the body
Explain the mechanism of malonate
Resembles succinate so acts as a competitive inhibitor and slows down the flow of electrons from succinate to ubiquinone by inhibiting oxidation of succinate to fumarate
Explain the mechanism of oligomycin
Binds to the stalk (gamma subunit) of ATP synthase and blocks the flow of protons through the enzyme
Explain the mechanism of dinitrophenol
Induces weight loss by transporting protons across the mitochondrial membrane thereby uncoupling oxidative phosphorylation from ATP production and therefore increasing metabolic rate and body temperature
Which metabolic poison uncouples ATP production from oxidative phosphorylation?
Dinitrophenol
Which metabolic poison binds to the stalk (gamma subunit) of ATP synthase?
Oligomycin
Which metabolic poison inhibits succinate dehydrogenase?
Malonate
Which metabolic poison binds to haemoglobin?
Carbon monoxide
Which metabolic poison binds cytochrome oxidase and inhibits it?
Cyanide
