How can bacteria reproduce by fission?

Answer 1

There are only two ways that single cell organisms can reproduce: fission and budding. Bacteria are too small and simple to reproduce by budding (budding is only used by a few single celled eukaryotes, never the simpler prokaryotes like bacteria).

Answer 2

Bacteria reproduce by a process called binary fission, where a single bacterium divides into two identical daughter cells. During fission, the bacterial chromosome replicates, and the two copies move to opposite ends of the cell. Then, the cell elongates, and a septum forms in the middle, dividing the cell into two. Finally, the cell membrane pinches inwards, resulting in the formation of two independent daughter cells.