hydrogenosomes

[Mouse]

I was just fascinated that we have multi cellular animals that can live with no oxygen.

 

But i am a bit curious about Hydrogenosomes? What are they? Some of the articles are a bit tough for me to understand.

 

Also how is this hydrogenosome allow the organism to make food and how is this in contrast with photosynthesis apart from the absence of light.

[CharonY]

Before delving deeper into the matter I should point out that you appear to confuse the production of nutrients (as e.g. C or N fixation) with energy production (i.e. ATP production). This are two separate processes. In hydrogenomsomes are, similar to mitochondria, involved in energy production. They do not create food.

[Moontanman]

Look here for info about hydrgenosomes

 

http://en.wikipedia.org/wiki/Hydrogenosome

[Mouse]

???:confused:

 

ok here's a diagram I hope someone can verify whether it's a theory or false.

 

I hope this doesn't meant that animals with hydrogenosomes do not breathe?

Edited April 26, 2010 by Mouse

[dttom]

I think species containing hydrogenosome is small enough that they don't have breathing. The organelle is found in small species as some fungi and protists, though the former could be potentially very large concerning with its mycelium. Also found in multicellular organism which is also microscopic. So the issue of breathing or not just doesn't make sense as they don't even have a breathing organ (not respiration but breathing).

[Mouse]

http://www.wired.com/wiredscience/2010/04/anoxic-animals/

 

 

So these animals dun breathe?

Edited April 28, 2010 by Mouse

[CharonY]

If I recall correctly all organisms with hydrogenosomes are anaerobic (I am less sure whether some may be facultative, though). So they do not breathe oxygen. Note that respiration does not necessary equals the use of oxygen as electron donor and that some (especially those in the field) often refer to respiration of any sort as breathing in am informal way.

[Mouse]

Ok if they dun breathe oxygen there must some substance like Fe 3+ .etc as a electron donor.

 

Am I asking the right questions?

[CharonY]

Fe3+ is not an electron donor, but an electron acceptor. During respiration it gets reduced to Fe2+.

To understand the relevance you have to understand another thing about respiration. Its purpose is not only to generate energy, but also to regenerate NAD+ from NADH. In addition, there are other ways of gaining energy, as e.g. substrate level phosphorylation (look those terms up, if you are unsure what they mean).

Now, if I recall correctly the hydrogenosomes do not possess ATP synthetases, which are required for energy production via respiration (and subsequent production of a proton gradient). However, they reduce H+ to hydrogen (hence their name) and thus take care of the electrons, while performing substrate level phosphorylation.

[Moontanman]

Hydrogenosomes do produce ATP

 

http://en.wikipedia.org/wiki/Hydrogenosome

 

A hydrogenosome is a membrane-enclosed organelle of some anaerobic ciliates, trichomonads and fungi. The hydrogenosomes of trichomonads (the most studied of the hydrogenosome-containing microorganisms) produce molecular hydrogen, acetate, carbon dioxide and ATP by the combined actions of pyruvate:ferredoxin oxido-reductase, hydrogenase, acetate:succinate CoA transferase and succinate thiokinase. Superoxide dismutase, malate dehydrogenase (decarboxylating), ferredoxin, adenylate kinase and NADH:ferredoxin oxido-reductase are also localized in the hydrogenosome. This organelle is thought to have evolved from anaerobic bacteria or archaea, though in the case of trichomonad hydrogenosomes the question remains open.

[CharonY]

However, they reduce H+ to hydrogen (hence their name) and thus take care of the electrons, while performing substrate level phosphorylation.

*cough* substrate level phosphorylation is ATP synthesis *cough*.

It is just not respiration.

Edited April 29, 2010 by CharonY