A Level Biology Practice Exam

What is aerobic respiration characterized by?

1. The absence of oxygen

2. The release of carbon dioxide

3. The production of lactic acid only

4. The release of energy without energy loss

The correct answer is: The release of carbon dioxide

Aerobic respiration is characterized by the release of carbon dioxide as a byproduct of the metabolic process that occurs in the presence of oxygen. During aerobic respiration, glucose is broken down with the help of oxygen, resulting in the production of ATP (adenosine triphosphate), which cells use for energy. The chemical reaction primarily involves the conversion of glucose and oxygen into carbon dioxide, water, and energy. This process is crucial for many organisms, including humans, as it allows them to efficiently extract energy from nutrients while maintaining a balanced exchange of gases. The release of carbon dioxide is a key indicator of aerobic respiration occurring in organisms, as it signifies the transformation of glucose, and the metabolic processes involved. In contrast, anaerobic respiration does not utilize oxygen and leads to different byproducts, such as lactic acid in some cases, which is why it is essential to note that aerobic respiration differs significantly in its outcomes and requirements.