Aerobic organism: Difference between revisions

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Revision as of 12:55, 4 April 2020 editKlaus Schmidt-Rohr (talk \| contribs)Extended confirmed users593 edits Balanced the chemical equation correctly and mentioned the energetic role of oxygen in aerobic cellular respiration.Tag: Visual edit ← Previous edit		Revision as of 16:05, 4 April 2020 edit undoMagic links bot (talk \| contribs)Bots291,110 editsm Replace magic links with templates per local RfC and MediaWiki RfC Next edit →
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	==Glucose==		==Glucose==
	A good example is the oxidation of ] (a ]) in ]:<ref name="Chauhan">Chauhan, B. S. (2008).''Principles of Biochemistry and Biophysics”. Laxmi Publications, p. 530. ISBN 978-8131803226</ref>		A good example is the oxidation of ] (a ]) in ]:<ref name="Chauhan">Chauhan, B. S. (2008).''Principles of Biochemistry and Biophysics”. Laxmi Publications, p. 530. {{ISBN\|978-8131803226}}</ref>

	:C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6 O<sub>2</sub> + 38 ] + 38 phosphate → 6 CO<sub>2</sub> + 44 H<sub>2</sub>O + 38 ]		:C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> + 6 O<sub>2</sub> + 38 ] + 38 phosphate → 6 CO<sub>2</sub> + 44 H<sub>2</sub>O + 38 ]

Revision as of 16:05, 4 April 2020

Aerobic and anaerobic bacteria can be identified by growing them in test tubes of thioglycollate broth:
1: Obligate aerobes need oxygen because they cannot ferment or respire anaerobically. They gather at the top of the tube where the oxygen concentration is highest.
2: Obligate anaerobes are poisoned by oxygen, so they gather at the bottom of the tube where the oxygen concentration is lowest.
3: Facultative anaerobes can grow with or without oxygen because they can metabolise energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more ATP than either fermentation or anaerobic respiration.
4: Microaerophiles need oxygen because they cannot ferment or respire anaerobically. However, they are poisoned by high concentrations of oxygen. They gather in the upper part of the test tube but not the very top.
5: Aerotolerant organisms do not require oxygen as they metabolise energy anaerobically. Unlike obligate anaerobes however, they are not poisoned by oxygen. They can be found evenly spread throughout the test tube.

An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment. In contrast, an anaerobic organism (anaerobe) is any organism that does not require oxygen for growth. Some anaerobes react negatively or even die if oxygen is present.

Types

Obligate aerobes need oxygen to grow. In a process known as cellular respiration, these organisms use oxygen to oxidize substrates (for example sugars and fats) and generate energy.
Facultative anaerobes use oxygen if it is available, but also have anaerobic methods of energy production.
Microaerophiles require oxygen for energy production, but are harmed by atmospheric concentrations of oxygen (21% O₂).
Aerotolerant anaerobes do not use oxygen but are not harmed by it.

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. Falcultative organisms grow in both oxygen rich media and oxygen free media

Glucose

A good example is the oxidation of glucose (a monosaccharide) in aerobic respiration:

C₆H₁₂O₆ + 6 O₂ + 38 ADP + 38 phosphate → 6 CO₂ + 44 H₂O + 38 ATP

where glucose releases the chemical energy stored in the relative weak double bond of oxygen.

This equation is a summary of what happens in three series of biochemical reactions: glycolysis, the Krebs cycle, and oxidative phosphorylation.

References

"aerobe" at Dorland's Medical Dictionary
^ Hentges DJ (1996). "17: Anaerobes:General Characteristics". In Baron S (ed.). Medical Microbiology (4 ed.). Galveston, Texas: University of Texas Medical Branch at Galveston. Retrieved 24 July 2016.
^ Kenneth Todar. "Nutrition and Growth of Bacteria". Todar's Online Textbook of Bacteriology. p. 4. Retrieved 24 July 2016.
Chauhan, B. S. (2008).Principles of Biochemistry and Biophysics”. Laxmi Publications, p. 530. ISBN 978-8131803226
Schmidt-Rohr, K. (2020). "Oxygen Is the High-Energy Molecule Powering Complex Multicellular Life: Fundamental Corrections to Traditional Bioenergetics” ACS Omega 5: 2221-2233. http://dx.doi.org/10.1021/acsomega.9b03352

Microbiology: Bacteria

Medical
microbiology

Biochemistry
and ecology

Oxygen preference	Aerobic Obligate Facultative Anaerobic Facultative Obligate Microaerophile Nanaerobe Aerotolerant
Other	Extremophile Human microbiome Gut Lung Mouth Skin Vaginal (in pregnancy) Placental Uterine Salivary Microbial metabolism Nitrogen fixation Microbial ecology Primary nutritional groups Substrate preference Lipophilic Saccharophilic

Shape

Structure

Cell envelope	Cell membrane Cell wall: Peptidoglycan NAM NAG DAP Gram-positive bacteria only: Teichoic acid Lipoteichoic acid Endospore Gram-negative bacteria only: Bacterial outer membrane Porin Lipopolysaccharide Periplasmic space Mycobacteria only: Arabinogalactan Mycolic acid
Outside envelope	Bacterial capsule Slime layer S-layer Glycocalyx Pilus Fimbria Non-motile bacteria
Composite	Biofilm

Taxonomy
and evolution

Categories:

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