Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

Which type of respiration occurs without the presence of oxygen?

1. Aerobic respiration

2. Cyclic respiration

3. Sequential respiration

4. Anaerobic respiration

The correct answer is: Anaerobic respiration

Anaerobic respiration is a metabolic process that occurs in the absence of oxygen. During this type of respiration, organisms convert glucose into energy through fermentation processes, resulting in byproducts such as carbon dioxide and alcohol or lactic acid, depending on the organism and conditions. This process is crucial for organisms such as yeast and some bacteria, which thrive in environments where oxygen is limited. In contrast, aerobic respiration requires oxygen to break down glucose, producing a significant amount of energy (ATP) and emitting carbon dioxide and water as byproducts. Cyclic and sequential respiration are not standard terms used to describe recognized forms of respiration in biological processes, which makes them less relevant in this context. Therefore, anaerobic respiration is the correct response as it identifies the type of respiration that functions without oxygen.