Which type of bacteria is defined as requiring oxygen to grow?

• A. Aerobic
• B. Anaerobic
• C. Facultative
• D. Microaerophilic

Answer: (A)

The main idea here is how bacteria obtain energy depending on oxygen. Those that require oxygen to grow rely on oxygen as the final electron acceptor in their respiration, which lets them generate energy efficiently through aerobic respiration. This makes them strictly dependent on oxygen, so the term that fits is aerobic.

In wastewater treatment, aerobic bacteria are the ones doing much of the organic matter breakdown because they need oxygen to power their metabolism.

Anaerobic bacteria don’t need oxygen and can even be harmed by it. Facultative bacteria can grow with or without oxygen, showing flexibility rather than a strict requirement. Microaerophilic bacteria need only a small amount of oxygen, not the full atmospheric level.