Certified Dietary Manager (CDM) Practice Exam

What defines anaerobic microorganisms?

1. They require oxygen to live

2. They can grow without the presence of oxygen

3. They are only found in aquatic environments

4. They produce energy through photosynthesis

The correct answer is: They can grow without the presence of oxygen

Anaerobic microorganisms are defined by their ability to grow without the presence of oxygen. This characteristic is vital for their survival and metabolism since they have adapted to thrive in environments where oxygen is scarce or entirely absent. These microorganisms can utilize various anaerobic metabolic pathways, such as fermentation, to produce energy, which allows them to survive in conditions that are hostile to aerobic organisms. The other choices describe characteristics that do not apply to anaerobic microorganisms. For instance, the requirement for oxygen indicates an aerobic lifestyle, which is contrary to what defines anaerobes. Being limited to aquatic environments is also inaccurate, as anaerobic microorganisms can inhabit various environments, including soil and digestive tracts. Finally, energy production through photosynthesis is a trait of certain phototrophic organisms, primarily found among plants and some bacteria, not anaerobes, as they do not rely on light for energy production.