Explain the role of endospores in the life cycle of certain prokaryotes. Explain the role of endospores in the life cycle of certain prokaryotes. When certain bacteria live inside a host, such as the bacteria that populate the digestive systems of many animals, they produce endospores to disperse within the host. An endospore is a reproductive structure produced by some bacteria. An endospore is reminiscent of a virus in that it has no metabolic activity but can parasitize a host cell to resume growth when conditions are favorable. Endospores provide a way for prokaryotes to survive conditions that are unsuitable for growth. The bacterial DNA is walled off from the rest of the cell, forming a resistant endospore that can resume growth when conditions are favorable.