What type of respiration requires oxygen?

Aerobic respiration is a metabolic process that requires oxygen to produce energy. In this process, glucose (or other substrates) is broken down with the help of oxygen to produce carbon dioxide, water, and adenosine triphosphate (ATP), which is the primary energy currency of the cell. This type of respiration is highly efficient, as it generates a significantly larger amount of ATP compared to other methods of energy production, such as anaerobic respiration and fermentation.

In aerobic respiration, each molecule of glucose can yield up to 36-38 ATP molecules due to the complete oxidation of glucose. The presence of oxygen allows for the complete breakdown of the substrates involved, leading to the release of more energy.

In contrast, anaerobic respiration does not require oxygen, relying instead on fermentation pathways that produce less energy. Fermentation and photosynthesis are different processes entirely; fermentation typically occurs in the absence of oxygen and results in byproducts such as lactic acid or ethanol, while photosynthesis involves capturing light energy to convert carbon dioxide and water into glucose and oxygen but is not a respiration process itself.

Thus, the definition and efficiency of aerobic respiration highlight why it is the type of respiration that requires oxygen.