Lastly, there is a group of gram-positive bacteria that is a large group of bacteria including the streptococci bacteria that cause strep throat, the lactic acid producing bacteria that turn milk into yogurt, the lactobacilli that cause tooth decay and soil bacteria that produce many antibiotics. There are two ways of reproduction in bacteria. Asexually, by binary fission, and sexually by conjugation. In binary fission the DNA replicates and then the cell pinches inward and splits in two, like mitosis. In conjugation two cells exchange a portion of their DNA across pili formed between the cells.
New material replaces old material in the cell.
This increases genetic variability in bacteria, but it is not true sexual reproduction. During unfavorable conditions the bacteria form endospores. Endospores contain the genetic information, so when favorable conditions return the bacteria can grow again. Bacteria can be classified by their shape and arrangement. Coccus means circular, bacillus means rod shaped and spirillus means spiral shaped.