EVERYDAY SCIENCE

Detailed explanation-1: -The two prokaryotic domains (Archaea and Bacteria) each comprise several smaller taxonomic groupings. Within the Archaea are the euryarchaeotes, crenarchaeotes, nanoarchaeotes, and korarchaeotes. Within the Bacteria are proteobacteria, chlamydias, spirochetes, cyanobacteria, and gram-positive bacteria.

Detailed explanation-2: -Examples of Prokaryotes For example, the famous (or infamous) Escherichia coli bacterium is a prokaryote, as is the streptococcus bacterium responsible for strep throat. The Streptomyces soil bacteria, from which the antibiotic streptomycin is derived, is also a prokaryotic organism.

Detailed explanation-3: -Examples of prokaryotes are blue-green algae, bacteria and mycoplasma. Among prokaryotes, bacteria are the most common and multiply very fast. They are single-celled and range in size from 0.2 to 10 microns (about 10 times smaller than most plant and animal cells).

Detailed explanation-4: -In the two-empire system arising from the work of Édouard Chatton, prokaryotes were classified within the empire Prokaryota. But in the three-domain system, based upon molecular analysis, prokaryotes are divided into two domains: Bacteria (formerly Eubacteria) and Archaea (formerly Archaebacteria).

Detailed explanation-5: -Prokaryotic cells are believed to be the oldest cells on Earth. Thus, all bacteria are prokaryotic, but not all prokaryotes are bacteria. The other major group of prokaryotes is the blue green algae (also known as cyanobacteria).