Most bacteria (including pathogens) are

Prepare for the Microbial Metabolism Test. Utilize flashcards and multiple choice questions with helpful hints and detailed explanations. Ace your test with ease!

Most bacteria obtain both their energy and their carbon from organic compounds, so they are chemoheterotrophs. They metabolize organic nutrients such as sugars, amino acids, and fatty acids for energy (via respiration or fermentation) and use those same organic molecules as the building blocks for growth. Pathogens especially rely on host-derived organic nutrients and do not fix CO2 or rely on light for energy, which is why this lifestyle best describes them. In contrast, phototrophs use light for energy, autotrophs fix CO2 for carbon, and chemotrophs refer to energy from chemical reactions without specifying the carbon source, which could be either organic or inorganic; the combination of both energy from chemicals and carbon from organic sources fits most bacteria.