Organism that thrives in an oxygenated environment
An aerobic organism or aerobe is an
organism that can survive and grow in an
oxygenated environment.[1] The ability to exhibit aerobic respiration may yield benefits to the aerobic organism, as aerobic respiration yields more energy than anaerobic respiration.[2] Energy production of the cell involves the synthesis of
ATP by an enzyme called
ATP synthase. In aerobic respiration, ATP synthase is coupled with an electron transport chain in which oxygen acts as a terminal electron acceptor.[3] In July 2020,
marine biologists reported that aerobic
microorganisms (mainly), in "
quasi-suspended animation", were found in
organically poor sediments, up to 101.5 million years old, 250 feet below the
seafloor in the
South Pacific Gyre (SPG) ("the deadest spot in the ocean"), and could be the
longest-living life forms ever found.[4][5]
When an organism is able to survive in both oxygen and anaerobic environments, the use of the
Pasteur effect can distinguish between facultative anaerobes and aerotolerant organisms. If the organism is using fermentation in an anaerobic environment, the addition of oxygen will cause facultative anaerobes to suspend fermentation and begin using oxygen for respiration. Aerotolerant organisms must continue fermentation in the presence of oxygen.
Facultative organisms grow in both oxygen rich media and oxygen free media.
Aerobic Respiration
Aerobic organisms use a process called
aerobic respiration to create ATP from ADP and a phosphate.
Glucose (a
monosaccharide) is oxidized to power the electron transport chain:[8]
C6H12O6 + 6 O2 + 38
ADP + 38 phosphate → 6 CO2 + 44 H2O + 38
ATP
In Oxidative phosphorylation, ATP is synthesized from ADP and a phosphate using ATP synthase. ATP synthase is powered by a proton-motive force created by using the energy generated from the electron transport chain. A
hydrogen ion (H+) has a positive charge and if separated by a cellular membrane, it creates a difference in charge between the inside and outside of the membrane. Oxidative phosphorylation occurs in the
mitochondria of
eukaryotes.[3]
Aerobic respiration needs O2 because it acts as the terminal electron acceptor in prokaryotes' electron transport chain. Molecular Oxygen is reduced to water in this process.[9]
^Hentges DJ (1996). "17: Anaerobes:General Characteristics". In Baron S (ed.).
Medical Microbiology (4 ed.). Galveston, Texas: University of Texas Medical Branch at Galveston.
ISBN9780963117212.
PMID21413255. Retrieved 24 July 2016.
^Chauhan BS (2008). Principles of Biochemistry and Biophysics. Laxmi Publications. p. 530.
ISBN978-8131803226.