Which bacteria grow only in the presence of oxygen?

Bacteria that require oxygen for growth are classified as obligate aerobes. These organisms utilize oxygen for cellular respiration, which is crucial for their energy production. In their metabolic processes, obligate aerobes rely on aerobic respiration, where oxygen serves as the final electron acceptor in the electron transport chain. This allows them to generate ATP efficiently, making them highly dependent on the presence of oxygen in their environment.

In contrast, obligate anaerobes are harmed or killed by oxygen and thrive in environments devoid of it, using alternative metabolic pathways such as fermentation. Facultative anaerobes can grow with or without oxygen, relying on aerobic respiration when oxygen is present but switching to anaerobic processes when it is not. Finally, extreme halophiles are specialized organisms that thrive in high-salt environments, and they do not have a specific requirement or preference for oxygen levels.

Overall, the key distinguishing feature of obligate aerobes is their absolute dependence on oxygen for survival and energy production.