Does an unicellular organism die..... if it does not get nutrient substancees for a long time?

Question

What I mean by death is that ... it does not replicate it's dna .... translate gene... carry out metabolic processes... as it normally does..... even when there are surplus nutrient elements.

If the answer is yes... Then the next question is: why?

It is understandable that without nutrient it cannot carry out many vital processes..... In this case it cannot carry out them for a long interval. But after that interval it has access to nutrient.... but it cannot manipulate them to continue life as it did before. What happened in this interval of lack of food that has irreversibly shifted to a place from which it cannot come back to manifest life?

How this shift (shift away from life) take place?

Answer 1

All ( or I guess I should say most because I don't know for sure) organisms need a carbon source.  Like glucose.  Organisms use the carbon source to make energy (in the form of ATP or NADH or one of those high energy bonds).  

The energy is used to carry out biological processes like DNA replication, cell division, protein synthesis, ion transport, etc etc.  Cells rely on these processes to stay alive and once the energy is used up they can't carry out these processes.  Ion gradients across membranes are lost.   Proteins break down.  The cell can't take in food anymore.  No energy can be made because the cell needed those gradients to make the energy in the first place.  Basically everything goes to equilibrium and while chemists think equilibrium is great biologists call it death.  

Sorry if that didn't make sense...