Question

an unknown organism was found with the following characteristics:

• cells do not contain a nucleus
• cell walls do not contain peptidoglycan
• lives in extreme environments (such as hot springs or salty lakes)

what domain would this organism be classified?
bacteria
archaea
eubacteria
eukarya

Explanation:

• Bacteria (including Eubacteria): Have cell walls with peptidoglycan. So the organism is not in the Bacteria domain (and thus not Eubacteria which is a part of Bacteria).
• Eukarya: Have cells with a nucleus. The organism's cells lack a nucleus, so it is not in Eukarya.
• Archaea: Are prokaryotes (no nucleus). Their cell walls lack peptidoglycan. Many Archaea live in extreme environments like hot springs or salty lakes.

Answer:

Archaea