Skip over navigation

The Citric Acid Cycle

Terms

Introduction

Before the Citric Acid Cycle

Acetyl Coenzyme A  -  A small molecule that carries acetyl functional groups in cells. Composed of an acetyl group attached to a coenzyme A molecule. The starting product of the citric acid cycle.
Acontinase  -  The citric acid cycle enzyme responsible for catalyzing the reaction that converts citric acid to isocitrate with the release of water.
Adenisine Triphosphate (ATP)  -  The molecule from which cells derive energy. Comprised of an adenisine molecule bonded to three phosphates, each phosphate bond contains energy, especially the third bond. By breaking that one bond and reducing ATP to adenisine diphosphate (ADP), the cell can get the energy to carry out its various processes.
Alpha-ketoglutarate dehydrogenase  -  The citric acid cycle enzyme responsible for catalyzing the reaction that converts alpha-ketoglutarate to succinyl-CoA with the release of carbon dioxide and the production of NADH from NAD.
Amphibolic  -  A term used to describe a process that has both anabolic and catabolic properties.
Anabolic  -  Term describing enzyme-catalyzed reactions in a cell that involves the synthesis of complex molecules out of simpler subunits and which uses energy.
Catabolic  -  Term describing enzyme-catalyzed reactions in a cell that involve the degradation of molecules into more simple subunits with the release of energy.
Citrate synthase  -  The citric acid cycle enzyme responsible for catalyzing the reaction that condenses acetyl-CoA with oxaloacetate to yield citric acid.
Citric acid cycle  -  Also known as the Krebs Cycle; a metabolic pathway found in aerobic organisms that oxidizes acetyl coA groups to carbon dioxide and water, producing 1 ATP, and a number of coenzymes that play a vital role in the next step of respiration, oxidative phosphorylation.
Coenzyme A  -  A molecule used to enzymatically transfer acetyl groups in a cell.
Dihydrolipoyl transacetylase  -  One of three enzymes that make up the pyruvate dehydrogenase multienzyme complex. Responsible for catalyzing the addition of a CoA molecule to the acetyl-lipoamide structure.
Flavin adenine dinucleotide  -  A coenzyme that participates in oxidation and reduction reactions by accepting and donating hydrogen atoms. Involved particularly in oxidations and reductions of carbon-carbon double and triple bonds.
Fumarase  -  The citric acid cycle enzyme responsible for catalyzing the reaction that converts fumarate to L-malate with the release of water.
Glycolysis  -  A metabolic pathway occurring in the cell cytosol. Glycolysis comprises a series of reactions that taken in their entirety convert glucose to pyruvate and synthesizes ATP.
Guanosine triphosphate  -  A molecule that is similar in both form and function to ATP.
Isocitrate dehydrogenase  -  The citric acid cycle enzyme responsible for catalyzing the reaction that converts isocitrate into alpha-ketoglutarate in a two-step mechanism that leads to the production of a molecule of NADH and carbon dioxide.
Malate dehydrogenase  -  The citric acid cycle enzyme responsible for catalyzing the reaction that converts L-malate into oxaloacetate with the production of a NADH molecule.
Metabolism  -  All the reactions occurring in an organism that participate in the acquisition or conversion of energy for use in the organism.
Oxaloacetate  -  Four-carbon molecule that binds with acetyl CoA in the first step of the citric acid cycle to form six-carbon citric acid. Over the course of a series of reactions, the citric acid is broken back down into two CO2 molecules and oxaloacetate, allowing for the cycle to being again while producing ATP and a number of coenzymes.
Oxidation  -  A reaction that involves the overall loss of electrons from a specific molecule or atom. Can occur with the addition of an oxygen or by the removal of a hydrogen.
Oxidative phosphorylation  -  A process occurring in the mitochondria that results in the formation of ATP from the flow of electrons to oxygen.
Pyruvate dehydrogenase  -  One of three enzymes that compose the pyruvate dehydrogenase multienzyme complex. Responsible for adding TPP to pyruvate with the release of carbon dioxide.
Pyruvate dehydrogenase multienzyme complex  -  An overarching name given to three enzymes which catalyze the reaction that converts pyruvate to acetyl-CoA.
Reduction  -  A reaction that results in the overall gain of electrons to a specific molecule or atom. Can occur with the addition of a hydrogen atom or by the removal of an oxygen atom.
Succinate dehydrogenase  -  The citric acid cycle enzyme responsible for catalyzing the reaction that converts succinate to fumarate with the production of a molecule of FADH.
Succinyl-CoA synthetase  -  The citric acid cycle enzyme responsible for catalyzing the reaction that converts succinyl-CoA to succinate.

Follow Us