Certified Wildlife Rehabilitator Practice Test

How do herbivores digest cellulose?

1. Through fermentation

2. By enzymatic breakdown

3. With the aid of carnivorous bacteria

4. By chemical synthesis

The correct answer is: Through fermentation

Herbivores digest cellulose primarily through fermentation, which is a process that occurs in specialized fermentation chambers in their digestive systems. These chambers, such as the rumen in ruminants, contain a complex community of microbes that produce enzymes capable of breaking down cellulose, a carbohydrate that is a major structural component of plant cell walls. The microbes ferment cellulose, converting it into simpler sugars and short-chain fatty acids, which can then be absorbed and utilized by the herbivore for energy. This symbiotic relationship between herbivores and their gut microbiota is crucial because herbivores lack the necessary enzymes to break down cellulose on their own. Therefore, fermentation allows them to extract nutrients from plant materials efficiently. In contrast, enzymatic breakdown alone is inadequate for digesting cellulose due to its complex structure, and the presence of carnivorous bacteria is irrelevant because these organisms do not aid in cellulose digestion. Chemical synthesis does not apply, as herbivores do not synthesize cellulose but rather break it down into usable components through fermentation.