Cells?

[juantonwan]

What's the difference between living and dead cells?

 

Can you duplicate the arrangement of atoms to create a living cell? How do you duplicate the information and the deciphering system?

[Mr Skeptic]

As far as I know the exact difference is really hard to tell. If you want a less exact difference, a living cell will have ATP, whereas a dead cell will not.

[pioneer]

The difference between live and dead cells is connected to energy. Without energy the DNA does not do anything. Although DNA might be able to replicate in some other circumstances, this is due to some stored energy capacitance, instead of dynamic energy streams like ATP.

 

Since energy is what drives the machinery of life, one would expect that energy also has some connection to genetic changes, since these can not occur unless there is some energy to drive it. We often look at life in the middle and not at the front end. Both can cause us to see the same thing in different ways.

 

For example, we have a machine that makes other machines. If we unplug it, it is a pile of metal and plastic that looks exactly like the one that is plugged in, but it doesn't do anything. If we plug it in, it gets powered up and starts to get busy again. If the current, going into the machine and/or moving between its components starts to get erratic, due to voltage changes, the machine may start to make mistakes, have pauses, trip a breaker, fry parts, etc.

 

If we don't consider the power source as being a source of any potential problem, it might looks like the machine's own parts are doing this. I suppose we can model that empirically, but cause and effect would never appear to be an option since we don't use that variable.

[Sisyphus]

There are lots of ways of being dead, just as there are lots of ways of a machine being broken. What's the difference between a working computer and a nonworking one? Sometimes it's obvious, sometimes it isn't (except that one works and one doesn't).

[pioneer]

If you look at the cell membrane, it acts like the largest dynamic capacitor for the cell. ATP energy is used to pump cations so the cell can store potential energy within the sodium/potassium cationic gradient. Many of the transport enzymes depend on this dynamic energy capacitance to help drive their transport mechanisms.

 

A defect in a transport protein, can impact how any enzyme works. While tweaking the dynamic energy capacitance of the membrane, we can create global changes in all the enzymes. This is done during cell cycles, using the unsaturation of the lipids within the membrane. This alters the energy potential by making the capacitor more subject to ion reversal and voltage drop.

 

Another way to store energy within a cell is by storing the energy as food chemicals. These chemicals have energy capacitance that is stored as chemical potential. When this chemical potential reaches a critical level, we have the energy needed to drive cell cycles.

[CharonY]

A dead cell does not have a membrane potential anymore. Pioneer, for energy conservation membrane potentials are generated passively to facilitate ATP generation. The rest does not make much sense either.

ATP still can be retained within a dead cell for a while, if no lysis occurs.

There a lot of different assays to determine the viability of different cells, primarily based on membrane integrity.

Edited March 5, 2010 by CharonY