Cellular Respiration and Fermentation Overview

fermentation

A metabolic process that converts sugar to acids, gases, or alcohol in the absence of oxygen.

aerobic respiration

A form of respiration that requires oxygen to produce energy from glucose.

cellular respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

redox reaction

A chemical reaction involving the transfer of electrons between two species.

oxidation/reduction

A chemical process in which the oxidation state of one or more substances changes.

NAD+/NADH

NAD+ is a coenzyme that acts as an electron carrier in cellular respiration; NADH is its reduced form.

electron transport chain

A series of protein complexes and other molecules that transfer electrons through a membrane to create a proton gradient.

glycolysis

The metabolic pathway that converts glucose into pyruvate, producing ATP and NADH in the process.

pyruvate oxidation

The process that converts pyruvate into acetyl CoA, producing NADH and CO2.

citric acid cycle

A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl CoA.

oxidative phosphorylation

The metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing energy which is used to form ATP.

substrate-level phosphorylation

A method of generating ATP by transferring a phosphate group directly to ADP from a phosphorylated intermediate.

acetyl CoA

A molecule that participates in many biochemical reactions in protein, carbohydrate, and lipid metabolism.

FAD/FADH2

FAD is a coenzyme that can accept two electrons and two protons to become FADH2, an electron carrier.

cytochromes

Proteins that contain heme groups and play a key role in the electron transport chain.

ATP synthase

An enzyme that creates ATP from ADP and inorganic phosphate during chemiosmosis.

chemiosmosis

The movement of ions across a selectively permeable membrane, down their electrochemical gradient.

proton-motive force

The force that promotes the movement of protons across membranes during ATP synthesis.

electrochemical gradient

A gradient that combines the concentration gradient and the electrical gradient across a membrane.

alcohol fermentation

A biological process that converts sugars into alcohol and carbon dioxide in the absence of oxygen.

lactic acid fermentation

A metabolic process by which glucose is converted into cellular energy and the metabolite lactate.

obligate anaerobes

Organisms that cannot survive in the presence of oxygen.

facultative anaerobes

Organisms that can survive with or without oxygen, using aerobic respiration when oxygen is present.

allosteric regulation

The regulation of an enzyme or protein by binding an effector molecule at a site other than the active site.