Chapter 9 Cellular Respiration and Fermentation Flashcards Preview

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Flashcards in Chapter 9 Cellular Respiration and Fermentation Deck (25):
1

Cellular respiration

The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP

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Fermentation

A catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) 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

The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP

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Redox- reaction

A chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another; short for reduction-oxidation reaction

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Oxidation

The complete or partial loss of electrons from a substance involved in a redox reaction

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Reduction

The complete or partial addition of electrons to a substance involved in a redox reaction

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Reducing agent

The electron donor in a redox reaction

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Oxidizing agent

The electron acceptor in a redox reaction

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NAD+

The oxidized form of nicotinamide adenine dinucleotide, a coenzyme that can accept electrons, becoming NADH. NADH temporarily stores electrons during cellular respiration

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NADH

The reduced form of nicotinamide adenine dinucleotide that temporarily stores electrons during cellular respiration. NADH acts as an electron donor to the electron transport chain

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Electron Transport Chain

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP

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Glycolysis

A series of reactions that ultimately splits glucose into pyruvate. Glycolysis occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration

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Citric acid cycle (krebs cycle)

A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA (derived from pyruvate) to carbon dioxide; occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration

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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 enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism

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Acetyl CoA

the entry compound for the citric acid cycle in cellular respiration, formed from a two-carbon fragment of pyruvate attached to a coenzyme

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Cytochromes

An iron-containing protein that is a component of electron transport chains in the mitochondria and chloroplasts of eukaryotic cells and the plasma membranes of prokaryotic cells

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ATP synthase

A complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes

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Chemiosmosis

An 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. Under aerobic conditions, most ATP synthesis in cells occurs by chemiosmosis

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Proton- motive force

The potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of hydrogen ions (H + ) across a biological membrane during chemiosmosis

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Alcohol fermentation

Glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD + and releasing carbon dioxide

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Lactic acid fermentation

Glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide

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Obligate anaerobes

An organism that carries out only 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