Humber Admissions Practice Test

What characterizes anaerobic respiration or fermentation?

1. It requires oxygen for energy production

2. It generates energy without using oxygen

3. It produces maximum ATP

4. It only occurs in plants

The correct answer is: It generates energy without using oxygen

Anaerobic respiration or fermentation is characterized by its ability to generate energy without the presence of oxygen. This process occurs when organisms rely on pathways, such as glycolysis, to break down glucose and produce energy under conditions where oxygen is not available. The end products of fermentation can vary, including lactic acid in animals and alcohol in yeast, depending on the type of organism and the specific fermentation pathway it uses. The key aspect of anaerobic respiration is that it does not utilize oxygen, which distinguishes it from aerobic respiration, where oxygen is necessary for generating ATP. As a result, anaerobic respiration is often less efficient in terms of the amount of ATP produced compared to aerobic processes, which is why it does not produce maximum ATP. Additionally, fermentation is not exclusive to plants; many types of organisms, including various bacteria and yeast, also perform anaerobic respiration. Therefore, the defining characteristic of fermentation is its capability to function effectively in an oxygen-free environment, producing energy through alternative biochemical processes.