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Key Terms

Key Terms

acetyl CoA: combination of an acetyl group derived from pyruvic acid and coenzyme A, which is made from pantothenic acid, a B-group vitamin

aerobic respiration: process in which organisms convert energy in the presence of oxygen

anaerobic: process that does not use oxygen

anaerobic cellular respiration: process in which organisms convert energy for their use in the absence of oxygen

ATP synthase: (also, F1F0 ATP synthase) membrane-embedded protein complex that adds a phosphate to ADP with energy from protons diffusing through it

chemiosmosis: process in which there is a production of adenosine triphosphate (ATP) in cellular metabolism by the involvement of a proton gradient across a membrane

citric acid cycle: (also, Krebs cycle) series of enzyme-catalyzed chemical reactions of central importance in all living cells

dephosphorylation: removal of a phosphate group from a molecule

fermentation: process of regenerating NAD⁺ with either an inorganic or organic compound serving as the final electron acceptor; occurs in the absence of oxygen

GLUT protein: integral membrane protein that transports glucose

glycolysis: process of breaking glucose into two three-carbon molecules with the production of ATP and NADH

isomerase: enzyme that converts a molecule into its isomer

Krebs cycle: (also, citric acid cycle) alternate name for the citric acid cycle, named after Hans Krebs who first identified the steps in the pathway in the 1930s in pigeon flight muscles; see citric acid cycle

oxidative phosphorylation: production of ATP using the process of chemiosmosis and oxygen

phosphorylation: addition of a high-energy phosphate to a compound, usually a metabolic intermediate, a protein, or ADP

prosthetic group: (also, prosthetic cofactor) molecule bound to a protein that facilitates the function of the protein

pyruvate: three-carbon sugar that can be decarboxylated and oxidized to make acetyl CoA, which enters the citric acid cycle under aerobic conditions; the end product of glycolysis

redox reaction: chemical reaction that consists of the coupling of an oxidation reaction and a reduction reaction

substrate-level phosphorylation: production of ATP from ADP using the excess energy from a chemical reaction and a phosphate group from a reactant

TCA cycle: (also, citric acid cycle) alternate name for the citric acid cycle, named after the group name for citric acid, tricarboxylic acid (TCA); see citric acid cycle

ubiquinone: soluble electron transporter in the electron transport chain that connects the first or second complex to the third