 In this video, we're going to have a look at the similarities and differences between prokaryotic and eukaryotic cells. All cells are either prokaryotic or eukaryotic. Organisms with prokaryotic cells are called prokaryotes, and organisms with eukaryotic cells are eukaryotes. Bacterian RK are prokaryotes, whereas plants, animals, fungi and all other organisms are eukaryotes. If the genetic material is enclosed by a nuclear envelope, so giving a definite nucleus, then they are eukaryotic, like this animal cell. Whereas in prokaryotic cells, there isn't a nuclear membrane and so no definite nucleus. The DNA is in the cytoplasm. We call a nucleus without a nuclear membrane a nucleoid. It isn't really a structure at all, it is simply the area in which the DNA exists. Prokaryotes were the first type of organisms to evolve and are still the most common organisms today. It is believed that the eukaryotes are evolved from prokaryotes. So the nucleus is a key factor in identifying whether a cell is prokaryotic or eukaryotic, but also the other organelles are too. Organelles are tiny structures within the cytoplasm that perform specific jobs, like the energy providing mitochondria in the animal cell. Eukaryotic cells contain lots of different organelles, whereas ribosomes are the only organelles found in prokaryotic cells. Ribosomes are where proteins are made. Organelles are very important to eukaryotic cells. Bacteria can get by without them because they are so small. Eukaryotic cells are still too small for our naked eye, but they are huge in comparison to prokaryotic cells. Organelles are an efficient way for eukaryotes to organize everything that is happening inside the cell. The cellular functions are compartmentalized, meaning different organelles carry out different processes, but bigger doesn't necessarily mean better. The small size and simplicity is an advantage to prokaryotes. It suits their lifestyle. Being small means they have a large surface area to volume ratio, and so they can easily meet their nutritional needs to grow quickly and multiply rapidly. So we know that prokaryotes don't have a nucleus and lack most other organelles. Our final thing to discover is that all prokaryotes are unicellular. They are defined as unicellular organisms that lack a membrane-bound nucleus. Eukaryotes can be either uni or multicellular. We looked at the differences between unicellular and multicellular in this video. The statement that all prokaryotes are unicellular is up for discussion, however, as there is a lot of evidence that show that bacteria species can aggregate together and divide labor. Thus forming a colony of cells that work more efficiently, this is a multicellular characteristic. However, there is a lot of resistance to calling any prokaryotes multicellular. So there we have nucleus-free prokaryotes and nucleus-containing eukaryotes. These are the main points from this video.