Which Statement is LEAST Characteristic of Proteobacteria

Question

Which statement is LEAST characteristic of proteobacteria?  
A) They live only inside plants.
B) Some eat other bacteria.
C) Some are chemoheterotrophs.
D) A member of this group gave rise to mitochondria.
E) They are the most diverse group of bacteria.

Accepted Answer

Proteobacteria are a diverse group of Gram-negative bacteria found in many different environments including soil, water, and animals. They are not limited to living only inside plants, making statement A the least characteristic. Bacteria that eat other bacteria are known as predatory bacteria and this behavior is somewhat common among proteobacteria. Many proteobacteria are chemoheterotrophs, meaning they obtain energy from organic compounds. One member of the proteobacteria, the ancestor of the mitochondria, is believed to have been engulfed by an early eukaryotic cell and became an endosymbiont. Proteobacteria are known for their diversity and include several well-known bacterial groups such as E. coli and Salmonella.