Unicellular Organism Survival on Single Substance

[cam875]

can an extremely simple unicellular organism survive off of one type of substance such as an extremely simple fat, and just break it down to use its energy. What would be the simplest type of fat or form of energy? Also if a simple unicellular organism doesn't want to do anything can it just stop all functions and when activiated by something just begin functioning again sort of like dying until a sensor goes off. Is that possible in an extremely basic organism?

 

[jim mcnamara]

You can think of bacteria as chemical factories. Many of them can use REALLY simple molecules as an energy source. The molecule does not have to organic either. Here is a Montana State news bulletin about an interesting find, a bacterium that eats nitrate and lives in salt water:

http://www.montana.edu/cpa/news/nwview.php?article=4144

Yes, some species of bacteria go into a resting phase - they are called spores. The spore "opens" when conditions are favorable to growth. Clostridium tetanii, the bacterium that causes tetanus, does this. It remains dormant in the soil for very long periods of time.

 

[cam875]

so what is the requirement for something to be used as energy for a living organism? having oxygen atoms in it? like nitrate?

 

[Charion]

Actually that is not quite right. Nitrate can be used as an electron acceptor within the respiration chain (instead of oxygen as we do). Alone it does not create any energy of course. The bacterium still requires to get electrons from an electron donor in the first place. A simple electron donor would be acetate, for instance.
This of, course only under the assumption that we talk about energy conservation and not active growth.

 

[cam875]

so what actually in essence creates the energy that an organelle could use for motion in the cell, is it the actual breakdown of organic molecules, sorry for all the questions I am just not understanding.