Table of Contents
Prokaryotes in Three Domains of Life: Bacteria and Archaea Biology Exam Guide
Master the three domains of life: Bacteria and Archaea are prokaryotes without nuclei, unlike eukaryotic Eukarya, with key differences in cell structure, DNA organization, and metabolism for General Biology certification success.
Question
Among the three domains of life, which of the following are prokaryotes?
A. Bacteria and Archaea
B. Bacteria and Eukarya
C. Archaea and Eukarya
D. Bacteria only
Answer
A. Bacteria and Archaea
Explanation
The three domains of life—Bacteria, Archaea, and Eukarya—classify all organisms based on cellular structure and genetic differences, with prokaryotes defined as single-celled organisms lacking a membrane-bound nucleus and organelles. Bacteria and Archaea are both prokaryotic, featuring circular DNA in a nucleoid region, ribosomes for protein synthesis, and cell walls (peptidoglycan in Bacteria, pseudopeptidoglycan or proteins in Archaea), enabling diverse metabolisms from soil decomposition to extremophile survival. Eukarya, however, are eukaryotic with nuclei housing linear chromosomes and organelles like mitochondria, distinguishing them in option B and C, while option D excludes Archaea despite their prokaryotic traits.