fermentation
a catabolic process, a partial degradation of sugars or other organic fuel that occurs without the use of oxygen
aerobic respiration
the most efficient catabolic pathway in which oxygen is consumed as a reactant along with the organic fuel
anaerobic respiration
the usage of substances other than oxygen as reactants in a process that harvests chemical energy
cellular respiration
includes both aerobic and anaerobic processes - relationship of aerobic respiration to organismal respiration, in which an animal breathes oxygen
redox reactions
oxidation-reduction reactions
oxidation
the loss of electrons from one substances
reduction
the addition of electrons to another substances - reduces the amount of positive charge of that atom
reducing agent
electron donor
oxidizing agent
electron acceptor
NAD+
nicotinamide adenine dinucleotide - a coenzyme electron carrier - can cycle easily between oxidized and reduced states - function as an oxidizing agent during respiration
electron transport chain
a process that breaks the fall of electrons to oxygen into several energy-releasing steps - mostly made up of proteins
glycolysis
a series of reactions that ultimately splits glucose into pyruvate - occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration
citric acid cycle
a chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA to carbon dioxide - occurs within mitochondrion in eukaryotic cells and in cytosol of prokaryotes
oxidative phosphorylation
the production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration
substrate-level phosphorylation
the enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism
acetyl CoA
acetyl coenzyme A - will feeds its acetyl group into citric acid cycle for further oxidation
cytochromes
protein electron carriers between ubiquinone and oxygen - prosthetic group has an iron atom that accepts and donates electrons
ATP synthase
the enzyme that actually makes ATP from ADP and inorganic phosphate - works like an ion pump running in reverse
chemiosmosis
the process in which energy stored in the form of hydrogen ion gradient across a membrane is used to drive cellular work
proton-motive force
drives hydrogen ions back across the membrane through H+ channels provided by ATP synthases
alcohol fermentation
in which pyruvate is converted to ethanol by releasing carbon dioxide from the pyruvate, which is converted to a two-carbon compound and is then reduced by NADH to ethanol - regenerates supply of NAD+ needed for the continuation of glycolysis
lactic acid fermentation
in which pyruvate is reduced directly by NADH to form lactate as an end product, with no release of CO2 - used when oxygen is scarce
obligate anaerobes
organisms that carry out only fermentation or anaerobic respiration - cannot survive in presence of oxygen
facultative anaerobes
organisms that can make enough ATP to survive using either fermentation or respiration
beta oxidation
a metabolic sequence that breaks teh fatty acids down to two-carbon fragments, which enter the citric acid cycle as acetyl CoA - NADH and FADH2 generation also resulting in further ATP production
fermentation
a catabolic process, a partial degradation of sugars or other organic fuel that occurs without the use of oxygen
aerobic respiration
the most efficient catabolic pathway in which oxygen is consumed as a reactant along with the organic fuel
anaerobic respiration
the usage of substances other than oxygen as reactants in a process that harvests chemical energy
cellular respiration
includes both aerobic and anaerobic processes - relationship of aerobic respiration to organismal respiration, in which an animal breathes oxygen
redox reactions
oxidation-reduction reactions
oxidation
the loss of electrons from one substances
reduction
the addition of electrons to another substances - reduces the amount of positive charge of that atom
reducing agent
electron donor
oxidizing agent
electron acceptor
NAD+
nicotinamide adenine dinucleotide - a coenzyme electron carrier - can cycle easily between oxidized and reduced states - function as an oxidizing agent during respiration
electron transport chain
a process that breaks the fall of electrons to oxygen into several energy-releasing steps - mostly made up of proteins
glycolysis
a series of reactions that ultimately splits glucose into pyruvate - occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration
citric acid cycle
a chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA to carbon dioxide - occurs within mitochondrion in eukaryotic cells and in cytosol of prokaryotes
oxidative phosphorylation
the production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration
substrate-level phosphorylation
the enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism
acetyl CoA
acetyl coenzyme A - will feeds its acetyl group into citric acid cycle for further oxidation
cytochromes
protein electron carriers between ubiquinone and oxygen - prosthetic group has an iron atom that accepts and donates electrons
ATP synthase
the enzyme that actually makes ATP from ADP and inorganic phosphate - works like an ion pump running in reverse
chemiosmosis
the process in which energy stored in the form of hydrogen ion gradient across a membrane is used to drive cellular work
proton-motive force
drives hydrogen ions back across the membrane through H+ channels provided by ATP synthases
alcohol fermentation
in which pyruvate is converted to ethanol by releasing carbon dioxide from the pyruvate, which is converted to a two-carbon compound and is then reduced by NADH to ethanol - regenerates supply of NAD+ needed for the continuation of glycolysis
lactic acid fermentation
in which pyruvate is reduced directly by NADH to form lactate as an end product, with no release of CO2 - used when oxygen is scarce
obligate anaerobes
organisms that carry out only fermentation or anaerobic respiration - cannot survive in presence of oxygen
facultative anaerobes
organisms that can make enough ATP to survive using either fermentation or respiration
beta oxidation
a metabolic sequence that breaks teh fatty acids down to two-carbon fragments, which enter the citric acid cycle as acetyl CoA - NADH and FADH2 generation also resulting in further ATP production