Topic 5 Cellular Respiration Vocabulary 1-30

catabolism

The breakdown of complex substances into simpler ones with release of energy.

cellular respiration

The catabolic pathways that break down organic molecules and use an electron transport chain to produce ATP.

aerobic respiration

A catabolic pathway for organic molecules that uses oxygen as the final electron acceptor and produces ATP.

anaerobic respiration

A catabolic pathway in which oxygen is not the final electron acceptor during the production of ATP by an electron transport chain.

fermentation

A catabolic process that makes a limited amount of ATP from organic molecules without an electron transport chain.

redox reactions

Chemical reactions that involve the complete or partial transfer of one or more electrons from one reactant to another.

oxidation

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

reduction

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

reducing agent

The electron donor in a redox reaction.

oxidizing agent

The electron acceptor in a redox reaction.

electron carrier

A compound that can accept a pair of high-energy electrons and transfer them, along with most of their energy, to another molecule.

NAD+ and FAD

Coenzymes that can easily be reduced to carry electrons to the electron transport chain.

NADH and FADH2

Reduced coenzymes that give high energy electrons to the electron transport chain.

electron transport chain

A sequence of membrane proteins that shuttle electrons down an electronegativity gradient in a series of redox reactionS that release the energy for making ATP.

glycolysis

A series of reactions that split glucose into pyruvate.

citric acid cycle (Krebs cycle)

An 8 step chemical cycle that completes the breakdown of glucose by oxidizing acetyl CoA to carbon dioxide.

oxidative phosphorylation

The production of ATP using energy from the redox reactions of an electron transport chain.

substrate-level phosphorylation

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

glycolysis: energy investment phase

The cell inputs 2 ATP to help break a glucose molecule.

glycolysis: energy payoff phase

Partial oxidation of molecules with production of 4 ATP.

pyruvate

Three-carbon compound that forms as an end product of glycolysis.

coenzyme A (CoA)

The coenzyme that is attached to a fragment of pyruvate to produce acetyl CoA.

acetyl CoA

The molecule that enters the citric acid cycle. It is formed when a fragment of pyruvate is attached to a coenzyme.

cytochromes

Proteins that accept and donate electrons in the electron transport chain.

ATP synthase

A complex of membrane proteins that uses the energy of a hydrogen ion concentration gradient to make ATP.

chemiosmosis

An energy coupling mechanism that uses the energy stored in a hydrogen ion gradient across a membrane to drive the production of ATP.

aerobes

Organisms that use oxygen in catabolism.

anaerobes

Organisms that do not use oxygen in catabolism.

alcohol fermentation

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

lactic acid fermentation

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