Dental Assistant Practice Exam

Facultative anaerobes can grow in what type of environment?

1. Only in the absence of oxygen

2. Only in the presence of oxygen

3. In either the presence or absence of oxygen

4. Only in highly acidic environments

The correct answer is: In either the presence or absence of oxygen

Facultative anaerobes are unique organisms that have the ability to grow in both the presence and absence of oxygen. This versatility allows them to adapt to varying environmental conditions. When oxygen is available, facultative anaerobes will typically utilize aerobic respiration for energy production, which is more efficient and yields a higher amount of ATP compared to anaerobic processes. In environments where oxygen is scarce or absent, these organisms can switch to anaerobic respiration or fermentation to generate energy, albeit less efficiently. This adaptability is crucial for survival in diverse habitats, which can fluctuate in oxygen availability. The ability to thrive in both environments distinguishes facultative anaerobes from obligate anaerobes, which can only survive in the absence of oxygen, and obligate aerobes, which require oxygen for growth. Thus, the correct answer reflects the unique metabolic capabilities of facultative anaerobes, enabling them to occupy a broader ecological niche.