About microscopic forms of life, including Bacteria, Archea, protozoans, algae and fungi. Topics relating to viruses, viroids and prions also belong here.
This is what wiki says:
Cyanobacteria include unicellular and colonial species. Colonies may form filaments, sheets or even hollow balls. Some filamentous colonies show the ability to differentiate into several different cell types: vegetative cells, the normal, photosynthetic cells that are formed under favorable growing conditions; akinetes, the climate-resistant spores that may form when environmental conditions become harsh; and thick-walled heterocysts, which contain the enzyme nitrogenase, vital for nitrogen fixation.
That just means they are not true multicellular prokaryotes.
Consider what you mean by "multicellular." To rule out streptococci, etc - bacteria found in multicellular associations . you'd have to ask for some level of differentiation and you do find this in cyanobacteria. To some extent you have this with many of the Actinomycetes.
First off, the question at hand is an oxymoron. The only somewhat correct answers are given by Adz and Jorge. Prokaryotes are not multicellular and saying that they are is contradictory to anything that is evidently known about them. Since the question is ambiguously termed, I am taking it in the context that you're asking if "prokaryotes are multi-cellular as the way eukaryotes are multi-cellular." Either way multicellular means an organism consisting of more than one cell. For example, a human being is a single organism, which consists of multiple cells. A bacterium is a single organism, so how many cells does a bacteria have? Thats the dead give away because bacteria only have one cell, they do not consist of multiple cells.
The answer is simply no, they are not multicellular like eukaryotes. Why? First, prokaryotes (bacteria) as a single entity (bacterium) are capable of carrying out their life processes individually of one another (reproduction, metabolism, nutrient processing, etc.), meaning one bacterium is able to live without an association to other bacteria. Second, if prokaryotes were multicellular their functions would depend on other bacterial cells making them "specialized cells" and would mean they were capable of forming tissues and organs. Now, this does not mean they can't function as a group and appear multicellular. Bacteria can even communicate with one another through chemical means or by interconnecting themselves with nanowires, which alters the way they behave as if they were living as a single bacterium.
In conclusion, bacteria are not multicellular because they can carry out their life processes as a single cell bacterium. However, they can communicate with one another and group or cluster with each other, but their biological life processes are still the same when grouped together. Each single bacterium in a group still maintains an individual life cycle, and does not depend on the group for survival.
***Also, Cyanobacteria were first classified as plants because of their ability to carry out photosynthesis, which both plants and cyanobacteria have the green pigment chlorophyll that allows them to carryout this process. However, cyanobacteria are bacteria and prokaryotic and are not plants. In fact, bacteria are the reason why we have photosynthesis, they carried out this process long before plants EXISTED. Did you know the first process of photosynthesis did not produce oxygen (anoxygenic photosynthesis) as a by-product! Bacteria eventually adapted to their environment and made a more suitable environment by producing oxygen as a by-product, which gave rise to the composition of our atmosphere and allowed for aerobic respiration, and also an abundance in the growth of other organisms.
I have sources if you need them, and not from wikipedia or the internet. This is presented in my own words, and not directly copied from something.
As pedantic a "no" as I've ever seen. I think readers will understand the nature of answers - both those suggesting and the response. It's noteworthy that some of the slime molds have what might be termed mutlicellular life shtages.
Sorry to be over the top with the response, but I find that it helps me learn the material better by summarizing what I read, and then explaining it in a way which I can understand. This entire forum is perfect for that.
I do suggest you try to understand the complexity of biology rather than so adamantly insist that it be forcefit into your lesson. Complicating the generalized concept that prokaryotes are "unicellular" is the funtional differentiation of cells in association with other cells of the same organism. You can see this in the cyanobacteria and streptomycetes and it's even more evident in the slime molds. As you progress in your understanding of biology, this will become even more evident.
Jorge what are you referencing to? I didn't complicate any concept of prokaryotes being unicellular. Also, you keep referring to cyanobacteria and slime molds. The question at hand is asking, are there multicellular prokaryotes, which I provided a fairly thorough and correct answer because there are no multicellular prokaryotes. Again with cyanobacteria, just because they appear in unicellular associations doesn't change the fact that they're still single-celled organisms and do not consist of multiple cells, thus their functions are still independent of one another. It seems you're using "multicellular" interchangeably to describe their unicellular associations, which doesn't make them truly multicellular organisms. And with slime molds you're comparing apples to oranges because my response didn't mention anything about eukaryotes not being unicellular.
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