Re: Can a cell live without a cytoplasm?

Hi David!

In short the answer to your question is "no".

A cell's cytoplasm is a complex mix of water, sugars, ions, proteins, and other molecules. Because of all these additives the cytoplasm is a very viscose liquid, probably better compared with Jell-O, than with water.

For a thing to be considered "alive", certain criteria must be fulfilled. Among these criteria are the existence of a metabolism, the capability of reproduction and reaction to external stimuli. There are others, but these three will do for the following explanation. All of them require the transport of material (chemical residues) and receptors or machines (enzymes) in form of proteins.

Without water the transport of molecules inside of a cell would break down. The cell would be left unable to react to internal or external stimuli, because no part of the cell would know what is happening in any other part. The metabolites (sugars, amino acids, etc.) necessary for life would never reach their destination. Without internal signaling the cell wouldn't know, when to start reproduction. Further, without water, the ion-concentration gradient over the membranes couldn't exist and cells would lose this helper in energy maintenance.

Worst of all, without water and ions, proteins would denaturate and cease to be functional. This happens, because the polar water coating and the loaded ions help bring a protein into it's functional form. Since proteins and nucleic acids (which would also drasticly change there conformation in lack of water) are the backbone of life as we know it, life could not exist without water as medium.

Of course, it is possible to imagine and "construct" a form of life, which is not dependent on water. I think, that a liquid as medium would be necessary in any of these constructs. Probably, that would then also qualify as cytoplasm, when it is combined with the molecules of that life-form.