In the first answer to How do we find antibiotics? @Ashafix claims that

Most bacteria have at least one cell wall

Does this mean that there are bacteria with more than one cell membrane? Which are those and how does that look/work? Are there different milieus in the different compartments?


  • $\begingroup$ Thanks! I will edit the original answer accordingly to make it more clear. $\endgroup$ – Ashafix Jun 4 '16 at 10:40

The phrase you quote is a little unclear, but in looking at the page you link to I believe that @Ashafix was referring to Gram-positive (one cell membrane) and Gram-negative bacteria (two cell membranes).

Each type has only one cell WALL, which refers to the structural peptidoglycan layer, which is between the two membranes in gram-negative bacteria, and is much larger in gram-positive bacteria.

The differences between these two cell types are of some interest with regard to the biology of what structures can sit in the cell membrane and how easy they are to work with in the lab, and how easy things are to get across the cell wall (w/r/t @Ashafix's original point).

  • $\begingroup$ Thanks, @Maximilian. Yes I got the original point of the refered to question. I was merely wondering just that which you answered. Thanks. As I'm only just signed up of this community, the only thing I can award you is the checkmark. Sorry. $\endgroup$ – Mats Jun 4 '16 at 8:54
  • $\begingroup$ great, glad that it got cleared up. no worries on votes or whatever. $\endgroup$ – Maximilian Press Jun 5 '16 at 18:00

I agree with @Maximilian that the phrase you quote is unclear, and we can't understand if it's talking about the number of cell walls of about the presence of cell walls:

Most bacteria have at least 1 cell wall, meaning that some bacteria can have more than 1

This is wrong, as @Maximilian explained. But this:

Most bacteria have a cell wall, meaning that some bacteria doesn't have any

Is correct. Tenericutes, a group of Eubacteria, don't have cell wall:


Reading the answer, it's clear that the user was talking about the outer membrane in Gracilicutes.

However, it's good to emphasize that all bacteria have only 1 cell membrane, because the outer membrane is not defined as a "cell membrane" (despite being a phospholipid bilayer): http://www.nature.com/nrmicro/journal/v13/n10/images/nrmicro3480-f1.jpg

  • $\begingroup$ Also enlightening. I wish I could up you as you deserve. As I commented on the answer above: I cannot award an up-votes due to lack of reputation of my own, but thank you very much for your interest and care. $\endgroup$ – Mats Jun 4 '16 at 9:00
  • $\begingroup$ No worries, mate! And good on you for giving @Maximilian the checkmark, a lot of people in SE communities ask the question and simply disappears after getting the answer. $\endgroup$ – user24284 Jun 4 '16 at 9:10
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    $\begingroup$ Well, how fun can it be to help those people when they ask their second question? It makes me glad and grateful that you people are around and give of your time and share your knowledge. That goes for all on SE that answers and discuss. @Maximilian too. $\endgroup$ – Mats Jun 4 '16 at 14:52
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    $\begingroup$ +1 @Gerardo, looking back I believe you have the right of it. $\endgroup$ – Maximilian Press Jun 5 '16 at 17:58

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