This may sound a bit strange question, but I am very new to biology. I would like to ask that do microorganisms like viruses, bacteria, amoebas, etc also contain water, as every living thing contains water?


The short answer, is yes, pretty much!

Do microorganisms contain water?*

Bacteria and eukaryotic microorganism

Bacteria and eukaryotic microorganism (incl. amoebas) have a membrane that separate the interior from the exterior. And yes, they have water inside, in which all chemical reactions take place.


Viruses, on the other hand, do not really have a membrane that separate the interior from the exterior. They are really just a bunch of proteins stick together. As such, it is hard to tell whether you would consider the water in which those proteins float part of the organism or not.

Note however, that some viruses have a viral envelope (that can be derived from host cell membrane). In such bacteria, there is more clearly an interior and an exterior and yes, there is water in the interior too! However, there is (except very few exceptions) no metabolism inside this envelope. This by the way part of the reason viruses are not considered alive.

Dehydrated living things

Note that some organisms can survive with very little water. Some seeds can survive extremely strong dehydration for example. Some tardigrades can also survive with less than 1% water in their body (see this New York Times article).

  • $\begingroup$ I think this answer is currently wrong Remi. Amoebas have endoplasm inside them. There is water in endoplasm and biochemical reactions require the presence of water but they take place in endoplasm. The same holds for other microorganisms. To me a strict interpretation of the question Are microorganisms made of water? is No, only water is made of water. $\endgroup$ – Michael_A Nov 19 '17 at 0:06
  • $\begingroup$ Yes, of course. I added the sentence "Of course, no living thing is made of 100% water. I will rather consider the question as meaning Do microorganisms contain water?" to clarify this point. Is it better? $\endgroup$ – Remi.b Nov 19 '17 at 0:11
  • $\begingroup$ @Michael_A you are technically correct... however, when you see that "also" at OP's question, you realize that they are simply talking about water as a constituent, as in the other organisms (presumably the visible, non-microscopic ones). $\endgroup$ – user24284 Nov 19 '17 at 0:12
  • $\begingroup$ @Remi.b Just edit OP's question title, since it's clear that OP made a small mistake. +1. Oh, and remove that "mini-micro" stuff. $\endgroup$ – user24284 Nov 19 '17 at 0:15
  • $\begingroup$ @GerardoFurtado Following your advice... $\endgroup$ – Remi.b Nov 19 '17 at 0:20

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