26 Questions
What is the main purpose of the malate-aspartate shuttle system?
To indirectly convey cytosolic NADH into mitochondria for oxidation
Why is the malate-aspartate shuttle considered the most active shuttle mechanism?
It depends on two transporters that allow for the exchange of malate and aspartate across the inner mitochondrial membrane
How does the malate-aspartate shuttle system indirectly convey cytosolic NADH into the mitochondrial matrix?
By using the exchange of malate and aspartate across the inner membrane to shuttle the electrons
What is the role of complex I in the malate-aspartate shuttle system?
Complex I receives the electrons shuttled from the cytoplasm to the matrix via the malate-aspartate system
What is the purpose of shuttling the electrons from cytosolic NADH into the mitochondrial matrix?
To allow NADH to be reoxidized to NAD+ in the mitochondria
What is the composition of the F1 subunit of the ATP synthase complex?
33
What is the role of the two b subunits (b2) in the Fo subunit of the ATP synthase complex?
They associate firmly with the and subunits of F1, holding them fixed relative to the membrane.
What is the role of the $eta$ subunits in the ATP synthase complex?
It is part of the mechanism that couples the rotation of the cylinder and $eta$ shaft to the synthesis of ATP.
What is the primary driving force for ATP synthesis in mitochondria?
The proton-motive force generated by the electron transport chain
Which of the following is NOT a component of the proton-motive force?
The difference in electron concentration across the inner mitochondrial membrane
What is the correct formula for calculating the free energy (ΔG) of the proton-motive force?
ΔG = RT ln (C2/C1) + ZFΔψ
In the chemiosmotic model for ATP synthesis, what is the role of the electron transport chain?
To generate a proton gradient across the inner mitochondrial membrane
Which of the following statements about the proton-motive force is correct?
It represents the temporary storage of energy from electron transfer reactions
In the formula for calculating the free energy (ΔG) of the proton-motive force, what does the term 'ZFΔψ' represent?
The electrical gradient component of the proton-motive force
What is the primary mechanism that regulates oxidative phosphorylation?
Availability of NADH and ADP/Pi
What is the function of the F-type ATPases?
They catalyze the hydrolysis of ATP to drive proton pumping
What is the role of the inhibitor of F1 (IF1) protein?
It prevents the hydrolysis of ATP by ATP synthase during hypoxia
What happens when oxidative phosphorylation is inhibited?
NADH accumulates, leading to feedback inhibition of glycolysis
Under what conditions is the IF1 protein active?
At lower pH levels encountered during hypoxia
What is the purpose of the coordinated regulation of ATP-producing pathways?
To ensure efficient energy production
What is the primary role of the adenine nucleotide translocase in the mitochondrial inner membrane?
It transports ADP into the matrix and ATP out of the matrix in an antiport mechanism.
How does the proton-motive force contribute to ATP synthesis and substrate transport in the mitochondrial matrix?
It provides the energy for ATP synthesis and facilitates the transport of ADP and Pi into the matrix.
What is the role of the phosphate translocase in the mitochondrial inner membrane?
It transports H2PO4- and H+ into the matrix in a symport mechanism.
What is the significance of the conformational change in the F1 beta subunits of the ATP synthase complex?
It causes a cooperative change that prevents ATP release until ADP and Pi are bound.
What is the net charge movement across the mitochondrial inner membrane during the transport of ADP and Pi into the matrix?
One negative charge is moved out of the matrix.
What is the driving force for the transport of H2PO4- into the mitochondrial matrix by the phosphate translocase?
The relatively low proton concentration in the matrix.
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