The Citric Acid Cycle

In the context of the three major stages of cellular respiration, what is the primary outcome of Stage 2?

What is the specific type of chemical reaction catalyzed by the pyruvate dehydrogenase (PDH) complex?

How many different coenzymes and prosthetic groups are required for the sequential action of the three enzymes in the pyruvate dehydrogenase complex?

The pyruvate dehydrogenase complex reaction is irreversible, with a standard free-energy change of -33.4 kJ/mol. What does this irreversibility imply?

Which cofactor of the pyruvate dehydrogenase complex accepts the hydroxyethyl group from TPP and transfers it to another cofactor?

What is the first reaction of the citric acid cycle, and what type of reaction is it?

What is the role of the iron-sulfur center in the enzyme aconitase?

The conversion of isocitrate to alpha-ketoglutarate by isocitrate dehydrogenase is the first of how many oxidation steps in the citric acid cycle?

The reaction catalyzed by succinyl-CoA synthetase is an example of what type of phosphorylation?

Succinate dehydrogenase, which catalyzes the oxidation of succinate to fumarate, is unique among the citric acid cycle enzymes for what reason?

The standard free-energy change for the malate dehydrogenase reaction is a highly positive 29.7 kJ/mol. How does the reaction proceed in the forward direction in the cell?

For each molecule of acetyl-CoA that enters the citric acid cycle, how many molecules of NADH are produced?

What is the total number of ATP molecules ultimately formed per turn of the citric acid cycle, assuming standard yields from oxidative phosphorylation?

The citric acid cycle is described as an amphibolic pathway. What does this term mean?

What is the primary purpose of anaplerotic reactions in relation to the citric acid cycle?

Which enzyme catalyzes the most important anaplerotic reaction in mammalian liver and kidney, and what cofactor does it require?

How is the pyruvate dehydrogenase (PDH) complex regulated by product inhibition?

In addition to allosteric regulation, how is the mammalian pyruvate dehydrogenase (PDH) complex regulated?

Which three enzymes of the citric acid cycle are the primary sites of regulation because they catalyze essentially irreversible reactions in the cell?

How does calcium ion (Ca2+) regulate the citric acid cycle in vertebrate muscle?

What is the primary purpose of the glyoxylate cycle?

Which two enzymes are unique to the glyoxylate cycle and are not found in the citric acid cycle?

Why can vertebrates, including humans, not convert fatty acids to glucose?

What is the standard free-energy change (delta G prime zero) for the oxidative decarboxylation of pyruvate to acetyl-CoA, catalyzed by the PDH complex?

The phenomenon where a single protein has more than one distinct function, such as aconitase acting as both an enzyme and an iron-regulatory protein, is known as what?