41 Questions
What is the primary function of electron carriers in the inner mitochondrial membrane?
To facilitate the transfer of protons during oxidative phosphorylation
Where are the citric acid cycle and B-oxidation enzymes located?
Mitochondrial matrix
What is the byproduct of the citric acid cycle and B-oxidation enzymes?
NADH and FADH
Why do enzymes in the mitochondrial matrix not need transporters?
Protons can enter the respiratory chain directly
What is the role of ATP synthase in the inner mitochondrial membrane?
To synthesize ATP from ADP and Pi
Where are the membrane transporters located?
Inner mitochondrial membrane
What is the function of pyruvate dehydrogenase?
To convert pyruvate into acetyl-CoA
What is the ATP yield for every mole of NADH used?
2.5 moles
What is the byproduct of the electron transport chain?
ATP and water
Where does oxidative phosphorylation occur?
Inner mitochondrial membrane
What percentage of the energy used by cells and body comes from the respiratory chain?
90%
How many molecules of ATP are formed when glucose is completely oxidized to CO2 and H2O?
30
What is the name of Complex I in the electron transport chain?
NADH Dehydrogenase
How many subunits are present in Complex I?
45
What is the role of CoQ in Complex I?
Receiving two protons or electrons
Where are the electrons transferred from in Complex I?
NADH to CoQ
What is the role of the β-subunits in the F1 subunit?
To facilitate catalytic activity or phosphorylation of ADP to ATP
What is the function of the γ-subunit?
To transmit rotational motion from the F0 subunit
What is the result of one complete rotation of the γ-subunit?
Three molecules of ATP are produced
What is the role of the α-subunits?
To undergo conformational changes in response to being attached to the γ-subunit
What is the function of the F0 subunit?
To transmit rotational motion to the F1 subunit
What is the name of the central stalk that transmits rotational motion from the F0 subunit?
Central stalk
What is the role of the δ and ε subunits?
To have structural functions
What is the binding change mechanism of the β-subunits?
Loose binding of ADP and Pi, then tight binding, then open state
What is the function of Thermogenin in brown adipose tissue?
To generate body heat
What is the effect of 2,4-Dinitrophenol on ATP synthesis?
It prevents proton passage through ATP synthase
Which inhibitor blocks the flow of protons through the ATP synthase?
Oligomycin
What is the effect of Complex I inhibitors on ATP synthesis?
No ATPs are formed for 1 NADH
What is the role of the adenine nucleotide transporter in mitochondria?
It transports ADP and ATP
What is the effect of Carbonyl cyanide m-chlorophenyl hydrazone (CCCP) on oxidative phosphorylation?
It uncouples the proton pump from ATP synthesis
What is the function of Gramicidin A in the context of oxidative phosphorylation?
It uncouples the proton pump from ATP synthesis
What is the effect of Rotenone on Complex I of the electron transport chain?
It blocks the flow of protons
What is the result of oxidation of protons and availability of oxygen during cellular contraction?
Increase in respiratory chain
What is the limiting factor in the respiratory chain when most cells are in the resting state?
Capacity of the respiratory chain
What happens to PO2 when the availability of oxygen is limited?
PO2 decreases below Km for heme a3
Which enzymes are deficient in fatal infantile mitochondrial myopathy and renal dysfunction?
Oxidoreductase enzymes in Complex I and III
What is the cause of MELAS syndrome?
Mutation in mitochondrial DNA
What is the function of uncoupling protein (UCP-1) in brown adipose tissue?
Uncouples ATP synthesis from respiration
What is the result of ATP being converted into ADP during cellular work?
Increased respiration
What is the relationship between oxygen availability and the respiratory chain?
Oxygen availability limits the respiratory chain
What is the result of increased respiratory chain activity during cellular contraction?
Increased ATP production
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