D2L Quizzes Ch. 11 Flashcards
(15 cards)
The regulatory mechanism in the Citrate cycle involving the NADH to NAD+ ratio is considered to be an example of regulation by
Product inhibition
Which of the three enzymes listed below catalyze reactions that restore citrate cycle intermediates?
Malic enzyme, pyruvate carboxylase, Phosphophenolpyruvate carboxykinase
Why does it make sense that under conditions of low ATP levels in the cell the Pyruvate carboxylase reaction is activated by acetyl CoA, whereas the pyruvate dehydrogenase reaction is activated by CoA under the same conditions?
When acetyl-CoA levels build up, then pyruvate carboxylase generates oxaloacetate for the citrate synthase reaction, whereas when CoA builds up, then acetyl-CoA needs to be generated by pyruvate dehydrogenase to maintain flux through the citrate cycle
What is the primary role of Phosphoenol pyruvate carboxylase in Malaga enzyme with regard to flux through the citrate cycle?
They catalyze in anaplerotic reactions to provide citrate cycle intermediates
What statement best describes the chemiosmotic theory proposed by Peter Mitchell?
Conversion of redox energy or light energy converted into potential energy is an electrochemical proton gradient
What statement best describes the mechanism of proton translocation via a redox driven conformational change?
Matrix derived protons are trans located across the mitochondrial membrane by altering PKA values of functional groups, located on the inner and outer faces of the membrane
As electrons from NADH past the electron transport system:
Protons are pumped across the mitochondrial membrane to generate a pH gradient
The purpose of the oxidative phosphorylation is to what
Convert redox energy from NADH and FADH2 into chemical energy ATP
Studies of the inner mitochondrial membrane reveal its composition to be approximately 20% lipid bilayer, an 80% protein. What is true of these proteins?
The protons are largely electron transport complexes in ATP synthase enzymes
What happens to the electron transport system, and oxidative phosphorylation pathway in the presence of excess NADH if the mitochondrial matrix weren’t closed, but opened up to the cytoplasm?
The ETS complexes would function as normal, but no ATP would be made
Which is the only electron carrier in the electron transport system that is not embedded in a membrane
cytochrome c
When the citric cycle is inhibited, which 2 metabolites are exported to the cytosol for fatty acid and cholesterol synthesis?
Citrate and malate
In the citrate cycle, a high concentration of NADH would result in
Inhibition of alpha, ketoglutarate dehydrogenase
A characteristic of complex III is that it
Uses the Q cycle mechanism to oxidize ubiquinone
Complex IV in the mitochondrial electron transport chain belongs to which enzyme class?
Oxidoreductase
