This document defines key terms related to autotrophs and heterotrophs, provides examples of each, compares their energy and carbon sources, diagrams a cyanobacterium, and summarizes how bacteria are used in bioremediation of soil and water. Specifically, it defines photoautotrophs, photoheterotrophs, chemoautotrophs, and chemoheterotrophs; uses cyanobacteria, Chloroflexus aurantiacus, Thiobacillus denitrificans, and Lactobacillus acidophilus as examples; and draws a table comparing chemoautotrophs and chemoheterotrophs. It also diagrams a filamentous cyanobacter