“Our cells” are eukaryotic cells, the same type found in other animals, plants and mushrooms. The other type of cells is prokaryotic cells, which bacteria and archea have. Procaryotic cells reproduce in the manner shown here.
Here is a short and easy read about binary fission. If you want to read more about mutatations in bacteria, Schroeder, Peesin, Simmons and Wang (2018) reviews the current knowledge of how bacteria mutate and the methods used to study it.
Khan Academy “Bacterial binary fission” https://www.khanacademy.org/science/biology/cellular-molecular-biology/mitosis/a/bacterial-binary-fission last accessed 6. february 2021
Schroeder, Yeesin, Simmons and Wang (2018) “Sources of spontaneous mutagenesis in bacteria” https://doi.org/10.1080/10409238.2017.1394262