USABO 9 : Cellular Respiration

Fermentation

The partial degradation of sugars or other organic fuel that occurs without the use of oxygen.

Aerobic respiration

The catabolic pathway in which oxygen is consumed as a reactant along with organic fuel.

Anaerobic respiration

A similar catabolic pathway that uses substances other than oxygen as reactants.

Redox reactions

Chemical reactions where one or more electrons are transferred from one reactant to another.

Oxidation

The loss of electrons from one substance in a redox reaction.

Reduction

The addition of electrons to another substance in a redox reaction.

Reducing agent

The substance that donates electrons and reduces another substance.

Oxidizing agent

The substance that accepts electrons by removing electrons from another substance.

NAD+

The oxidized form of the coenzyme electron carrier that functions as an electron acceptor.

NADH

The reduced form of NAD which represents stored energy that can be tapped for ATP during cellular respiration.

Dehydrogenases

Enzymes that remove pairs of hydrogen atoms from substrates and deliver them to coenzymes.

Electron transport chain

A system of molecules, mostly proteins, that shuttle electrons down a series of redox reactions to O2.

Glycolysis

The first catabolic pathway in cellular respiration which breaks glucose into two pyruvate molecules.

Citric Acid Cycle

The stage in cellular respiration where the breakdown of glucose into carbon dioxide is completed.

Oxidative phosphorylation

The usage of energy received from the electron transport chain to make ATP from ADP.

Substrate-level phosphorylation

The mode of ATP synthesis that transfers a phosphate group from a substrate molecule to ADP.

Pyruvate oxidation

The oxidation of pyruvate into acetyl CoA in eukaryotes.

Chemiosmosis

The process of using the energy stored in a hydrogen ion gradient to drive cellular work such as ATP synthesis.

ATP synthase

The enzyme that catalyzes the production of ATP from ADP and inorganic phosphate.

Facultative anaerobes

Organisms that can produce ATP via either fermentation or respiration.

Beta oxidation

A metabolic sequence that breaks down fatty acids into two-carbon fragments that enter the citric acid cycle.

Phosphofructokinase

An enzyme that controls the rate of cellular respiration and is inhibited by AMP from ADP.