Talk:Anaerobic respiration

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Article Grading: The following comments were left by the quality and importance raters: (edit · history · refresh · how to use this template) Rated high as high school/SAT biology content. This article overlaps with fermentation (biochemistry). - tameeria 23:11, 18 February 2007 (UTC)

Contents 1 "Lactic acid" fermentation 2 Merge with fermentation (biochemistry) 3 Energy released? 4 Vandalism 5 No O2 in Krebs' 6 Incomprehensible 7 Unclickable metabolic map 8 Respiration is NOT the same as Fermentation

[edit] "Lactic acid" fermentation

The equations for anaerobic respiration using lactic acid fermentation are always given as
C6H12O6 --> 2 C3H6O3
and this lactic acid production causes acidosis (resulting in muscle fatigue)
but it is actually
C6H12O6 --> 2 CH3CH3COO- + 2H+
CH3CH3COO- is always produced in salt form and the net H+ production is due to a greater rate of ATP hydrolysis than can be matched by oxidative phosphorylation, meaning that acidosis is not caused by "lactic acid" fermentation. On the contrary, lactate acts in one of the membrane exchange systems for cell proton buffering -- sarcolemmal transport of protons out of the cytosol through lactate/H+ symporters.
The reference I found is http://ajpregu.physiology.org/cgi/reprint/287/3/R502.pdf. It seems to me that the current textbooks have maintained the possible misconception of acidosis due to lactic acid as well. Can an expert clarify this? I just found the perhaps more accurate account given in the article on lactic acid
Lim Wei Quan 10:55, 24 May 2007 (UTC)

[edit] Merge with fermentation (biochemistry)

I propose a merge with, and migration from, fermentation (biochemistry). The biochemistry of fermentation is anaerobic respiration of sugars to ethanol. Zephyris _Talk 13:57, 4 November 2006 (UTC)

• This would be absoultely insane, the two processes are approaced totally differently in biology. This proposal is more suited to the title of an essay for undergraduates than a serious encyclopedia.

as far as i know, fermentation has been a topic for year 2 Higher diploma which major in biotechnology in Hong Kong already. back to the matter, i don't agree with the merge since they are totally different in both meaning and process. meaningless 16:49, 12 December 2006 (UTC)

In an attempt to clean the article up a little bit, I added a new heading, "Anaerobic fermentation in prokaryotes," which includes a very brief explanation of the difference between the two processes. I don't feel quite bold enough to delete the fermentation sections since there are so many people out there that use the two terms interchangeably. There are many web sites, including several wikipedia articles, that confuse the two processes. NighthawkJ 17:46, 28 November 2006 (UTC)

• I vote a definite no on the proposal to merge. The terms "anaerobic respiration" and "fermentation" are not interchangeable. The breakdown of glucose to lactic acid described in the current version of the article is an example of fermentation, not anaerobic respiration. Anaerobic respiration, like aerobic respiration, involves an electron transport chain, with the terminal electron acceptor being something other than oxygen. The electron transport chain is not involved in the fermentation of glucose to lactic acid or ethanol. Therefore, descriptions of lactic acid and ethanol fermentation need to be removed from this article and replaced with examples of anaerobic respiration. NighthawkJ 05:49, 17 November 2006 (UTC)

This is true, but anaerobic respiration, which is defined as "the oxidation of molecules in the absence of oxygen to produce energy" includes fermentation as a specific example of non-electron chain anaerobic respiration.—The preceding unsigned comment was added by Zephyris (talk • contribs) 08:21, 17 November 2006.

Actually, the definition isn't quite correct. Anaerobic respiration is defined as "the oxidation of molecules in the presence of an external electron acceptor (other than oxygen) to produce energy." The use of an external electron acceptor requires an electron transport chain. Fermentation clearly does not fit this definition since it does not involve an external electron acceptor. In fermentation, a molecule derived from the partial oxidation of glucose, pyruvate, is used as an internal electron acceptor. This is an important distinction because the partial oxidation of glucose in fermentation does not permit the synthesis of as much ATP as observed with the complete oxidation of glucose observed with anaerobic respiration. Complete glucose oxidation is possible in anaerobic respiration because of the use of an external electron acceptor via an electron transport chain. I'm open to the possibility that other fields use the definition currently stated in the article, but the bacterial physiology textbooks that I've seen all make a distinction between fermentation and anaerobic respiration. NighthawkJ 04:44, 18 November 2006 (UTC)

That point had eluded me. -- Paleorthid 15:59, 18 November 2006 (UTC)

Fully agree with Nighthawk - and want to actuallt further clarify that fermentation may involve intermediate reactions that involve oxidation and reduction, but there is not NET oxidation in fermentation - i.e. whaever molecule (such as glucose) you start with, neither gains nor loses electrons if you compare it to the FINAL products of the fermentation reaction - and this is exactly because there is no EXTERNAL terminal electron acceptor. - DocMelvis (talk) 06:58, 26 April 2008 (UTC)

• I support(support withdrawn per above -- 15:59, 18 November 2006 (UTC)) the proposal to merge, but with some misgivings about my POV. Certainly fermentation is more commonly viewed as related to fermentation (food) or industrial fermentation, I have no misgivings about that. But fermentation has many subtle biochemical nuances that are fascinating in their own right: is a discussion in the offing for fermentation-related products like aldehyde, alkene, ester, ketone, and epoxide? Will it fit into anaerobic respiration? into fermentation? I simply don't have a good idea. My support(support withdrawn per above -- 15:59, 18 November 2006 (UTC)) for merge is based on what I know. In biogeochemistry applications (wetland chemistry, bioremediation) and in waste treatment, fermentation is not a term commonly used, despite indications to the contrary in industrial fermentation. This is because fermentation is only one of the anoxic and anaerobic processes that occur in sequence, one minor sub-step down the biogeochemical redox ladder, with carbon dioxide and water generation at the top and hydrogen generation at the bottom. See this PPT. Thus covering fermentation in anaerobic respiration is fine from my perspective. -- Paleorthid 17:50, 17 November 2006 (UTC)

I have to agree, please don't merge the two. In Microbiology, they are two distinct pathways!

• Good debate! I will take down the merge tags, although there are clarification issues which need to be addressed for the casual reader. Thank you for your comments :) - Zephyris _Talk 00:02, 12 December 2006 (UTC)

From an exercise/physical therapy perspective, the two topics are very different. We do not talk about fermentation occurring during exercise.

• It is a valid point that under different circumstances these terms carry different meanings, however because not all situations use them interchangably or misuse them according to some definitions they deserve separate pages. The page essentially needs a large restructure with sections for each major use of the term 'anaerobic respiration' and an explanation of its use in that situation.

In the case you mention it may be as simple as putting "For the process of anaerobic respiration in mammalian (human) muscle see: Fermentation (biochemistry)"... In fact, I think ill do that! - Zephyris _Talk 23:15, 12 December 2006 (UTC)

I would edit it but im having bizzarre problems with my keyboard... I have edited fermentation (biochemistry) to emphasise its position as anaerobic respiration with no external electron acceptor. - Zephyris _Talk 23:58, 12 December 2006 (UTC)

[edit] Energy released?

This cites the energy released as 120 kJ - is that supposed to be kilojoules (way too high), kilojoules/mole, some other unit than kJ? What's the deal?

[edit] Vandalism

Why is this page being vandalised on a regular basis? JFW | T@lk 22:26, 13 Nov 2004 (UTC)

Probably just young kids at school etc. —Preceding unsigned comment added by 213.162.124.224 (talk) 12:04, 19 May 2008 (UTC)

[edit] No O2 in Krebs'

There is no O2 within the action of the Krebs' Cycle, but only takes place under aerobic conditions. How is this?

It's because the Krebs' cycle will not advance without NAD+. JFW | T@lk 09:12, 17 Dec 2004 (UTC)

Isn't there also 'anaerobic respiration' using sulphide or nitrogen containing molecules?

Doesn't it say that, even if only briefly. See Anaerobic_respiration#Fermentation_in_other_organisms David D. (Talk) 13:30, 12 July 2006 (UTC)

[edit] Incomprehensible

What on earth does this mean: "The end product of fermentation in C. perfringens is a gas which causes the condition of gas. When the Oxygen levels are low, it takes turn to give out a β helix."

I deleted these two sentences since C. perfringens carries out fermentation, not anaerobic respiration. NighthawkJ 17:49, 28 November 2006 (UTC)

+ Addition (jccnoon (Talk)) This article is far too technical and specialized, it should have at the very least an alternative introduction for those with less of an understanding in the field.

[edit] Unclickable metabolic map

The disclosable metabolic map insert at the bottom has a legend that says the pathways are clickable, but they are *not*. How to correct this? Does anyone know? Rudd-O 01:28, 5 June 2007 (UTC)

[edit] Respiration is NOT the same as Fermentation

Respiration (be it aerobic or anaerobic) is fundamentally different from fermentation and I join whoever is disputing the factual accuracy of this article as the article is at the very least ambiguous about clearly differentiating between the two. I can provide further details and references at a leter time, but I just wanted to put this out there now try to warn readers from assuming that all the information presented is true and reliable. I also fully oppose any suggestions to merge this topic with fermentation.

DocMelvis (talk) 06:50, 26 April 2008 (UTC)