What type of atmosphere is required for strict anaerobic growth?

What type of atmosphere is required for strict anaerobic growth?

• A. Reduced O2
• B. No O2
• C. Reduced CO2
• D. Elevated CO2

Answer: (B)

Strict anaerobic organisms require an environment that is devoid of oxygen (O2) for growth. This is because these organisms have metabolic pathways that do not utilize oxygen and may even find it toxic. In the absence of oxygen, strict anaerobes rely on fermentation or anaerobic respiration to generate energy. Oxygen can lead to the production of harmful reactive oxygen species, which can damage cellular components, leading to cell death in these microbes. The other choices involve alterations to the atmospheric composition but do not create the complete absence of oxygen necessary for strict anaerobes. Reduced O2 implies a decreased but not absent level of oxygen, which is unsuitable for strict anaerobes. Reduced CO2 and elevated CO2 adjustments relate to the carbon dioxide levels in the atmosphere, which do not directly impact the growth of strict anaerobes in terms of their fundamental requirement for oxygen-free environments. Thus, the absence of oxygen is a defining characteristic that allows strict anaerobes to thrive, highlighting why the choice indicating “no O2” is the correct response.

Strict anaerobic organisms require an environment that is devoid of oxygen (O2) for growth. This is because these organisms have metabolic pathways that do not utilize oxygen and may even find it toxic. In the absence of oxygen, strict anaerobes rely on fermentation or anaerobic respiration to generate energy. Oxygen can lead to the production of harmful reactive oxygen species, which can damage cellular components, leading to cell death in these microbes.

The other choices involve alterations to the atmospheric composition but do not create the complete absence of oxygen necessary for strict anaerobes. Reduced O2 implies a decreased but not absent level of oxygen, which is unsuitable for strict anaerobes. Reduced CO2 and elevated CO2 adjustments relate to the carbon dioxide levels in the atmosphere, which do not directly impact the growth of strict anaerobes in terms of their fundamental requirement for oxygen-free environments.

Thus, the absence of oxygen is a defining characteristic that allows strict anaerobes to thrive, highlighting why the choice indicating “no O2” is the correct response.