Tennessee Wastewater Operator Practice Exam

What type of bacteria are characterized by obtaining energy from the breakdown of organic matter?

1. Autotrophic bacteria

2. Heterotrophic bacteria

3. Nitrifying bacteria

4. Denitrifying bacteria

The correct answer is: Heterotrophic bacteria

Heterotrophic bacteria are defined by their reliance on organic compounds for energy and carbon. They play a vital role in the ecosystem by decomposing organic matter, which contributes to nutrient cycling and soil health. These bacteria can digest and utilize complex organic materials, breaking them down into simpler compounds that can then be absorbed and transformed into energy. Unlike autotrophic bacteria, which synthesize their own food typically through processes like photosynthesis or chemosynthesis, heterotrophic bacteria depend on existing organic molecules. This distinction is crucial in wastewater treatment processes, where heterotrophic bacteria help in the breakdown of organic pollutants, thereby aiding in the purification of water. Nitrifying and denitrifying bacteria are specialized types of bacteria that are involved in specific biochemical processes related to nitrogen cycling, rather than general organic matter decomposition. Thus, they don’t fit the definition related to energy acquisition from organic matter in the same way that heterotrophic bacteria do.