VOCABULARYAP Biology Ch. 9 – Cellular Respiration

•Catabolic pathway•Fermentation•Aerobic respiration•Anaerobic respiration•Cellular respiration•Redox reaction•Oxidation/reduction•Reducing agent•Oxidizing agent•NAD+•Electron transport chain•Glycolysis•Citric acid cycle•Oxidative phosphorylation

•Substrate- level phosphorylation

•Pyruvate•Acetyl CoA•Cytochromes•ATP synthase

•Chemiosmosis•Proton-motive force•Alcohol fermentation•Lactic acid fermentation•Obligate anaerobes•Facultative anaerobes•Beta oxidation

Catabolic Pathway A metabolic pathway that releases

stored energy by breaking down complex molecules

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Fermentation Catabolic process that makes a limited

amount of ATP from glucose without an electron transport chain and that produces a characteristic end product such as ethyl alcohol or lactic acid

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Aerobic Respiration Catabolic pathway that consumes

oxygen and organic molecules, producing ATP.

This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms

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Anaerobic Respiration The use of molecules other than oxygen

to accept electrons at the end of the electron transport chain

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Cellular Respiration The catabolic pathways of aerobic and

anaerobic respiration which break down organic molecules for the production of ATP

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Redox Reaction Oxidation-Reduction Reaction A chemical reaction involving the

complete or partial transfer of one or more electrons from one reactant to another

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Oxidation/Reduction Oxidation – the loss of electrons from

one substance in a Redox Reaction

Reduction – the addition of electrons to another substance in a Redox Reaction

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Reducing Agent/Oxidizing Agent The electron donor in a Redox Reaction

is the reducing agent The electron acceptor in a Redox

Reaction is the oxidizing agent

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NAD+ A coenzyme that is the electron carrier

that receives the hydrogen atom (1 proton and 1 electron) before it continues on to oxygen in energy releasing steps

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Electron Transport Chain A sequence of electron carrier

molecules that shuttle electrons during the redox reactions that release energy used to make ATP

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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

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Substrate-level Phosphorylation The formation of ATP by an enzyme

directly transferring a phosphate group to ADP from an intermediate substrate in catabolism

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Glycolysis The splitting of glucose into pyruvate. Occurs in almost all living cells Serves as the starting point for

fermentation and cellular respiration

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Pyruvate Ionized form of pyruvic acid During glycolysis glucose is split into two

three-carbon sugars and these smaller sugars are then oxidized and rearranged to form two molecules of pyruvate

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The Citric Acid Cycle Also called the Krebs Cycle Takes place within the mitochondrial

matrix of eukaryotic cells or the cytosol of prokaryotes

Second major phase of cellular respiration

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Acetyl CoA Acetyl coenzyme A Pyruvate is transformed to Acetyl CoA in

the citric acid cycle

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Cytochromes Iron-containing protein that is a

component of electron transport chains in the mitochondria of eukaryotic cells as well as the plasma membrane of prokaryotic cells

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ATP Synthase A complex of several membrane proteins

that provide a port though which proteins diffuse. This complex functions in chemiosmosis with adjacent electron transport chains, using energy of a hydrogen ion (proton) concentration gradient to make ATP. Found in mitochondrial membrane in eukaryotic cells and the plasma membrane of prokaryotes

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Chemiosmosis Energy coupling mechanism that uses

energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work such as the synthesis of ATP. Most ATP synthesis in cells occurs by chemiosmosis

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Proton-Motive Force The potential energy stored in the form

of an electrochemical gradient, generated by the pumping of hydrogen ions across a biological membrane during chemiosmosis

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Alcohol Fermentation Glycolysis followed by followed by the

conversion of pyruvate to carbon dioxide and ethyl alcohol

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Lactic Acid Fermentation Glycolysis followed by the conversion of

pyruvate to lactate, with no release of carbon dioxide

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Obligate Anaerobes An organism that only carries out

fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it

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Facultative Anaerobes An organism that makes ATP by aerobic

respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present

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Beta Oxidation A metabolic sequence that breaks fatty

acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA

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