Exam 3: Cellular Respiration Flashcards
cellular respiration
the catabolic (breakdown) pathways in which the chemical bond energy in organic molecules is released and trapped to build ATP
chemiosmosis
an energy-coupling process in which the diffusion of protons through the ATP synthase protein complex drives ATP synthesis
ATP synthase
a complex of membrane proteins that functions in ATP synthesis from ADP and a phosphate, using energy from protons flowing through the synthase from high concentration to low concentration
redox reaction
a chemical reaction in which an electron is transferred from one chemical substrate to another; gain of electrons is reduction, and loss of electrons is oxidation
electron transport chain
a series of membrane molecules that are reduced and oxidized as electrons move sequentially towards more electronegative acceptors, losing potential energy at each step
FAD (flavin adenine dinucleotide)
a coenzyme carrier that serves as an electron shuttle as it is reduced to FADH2 in the Krebs cycle and oxidized back to FAD in the electron transport chain
NAD+ (nicotinamide adenine dinucleotide)
a coenzyme carrier that serves as an electron shuttle as it is reduced to NADH (with H+) in glycolysis and the Krebs cycle and is oxidized back to NAD+ in the electron transport chain or during fermentation
glycolysis
a pathway of ten cytosolic reactions that split glucose and oxidize it to form pyruvic acid while producing ATP and reduced NADH; the first major stage in cellular respiration
Krebs cycle or citric acid cycle
a pathway of eight reactions that oxidize acetyl to carbon dioxide, producing several molecules of reduced NADH and also some ATP and reduced FADH2; the second major stage in cellular respiration
fermentation
an anaerobic process in which pyruvate from glycolysis is converted to other organic molecules to provide recovery of oxidized NAD+
oxidative phosphorylation
the production of ATP by ATP synthase, joining ADP to a phosphate ion in solution by condensation, using energy from the proton gradient derived from redox reactions in the electron transport chain
substrate-level phosphorylation
the production of ATP that occurs when an enzyme transfers a phosphate group from another organic substrate directly onto ADP
mitochondria
the organelle in eukaryotic cells where aerobic respiration reactions occur, with Krebs Cycle enzymes in the mitochondrial matrix and electron transport chain and ATP synthase molecules located in the inner membrane
aerobic
a metabolic process or organism that requires oxygen gas
anaerobic
a metabolic process or organism that does not require oxygen gas