How are organisms in the domains Bacteria and Archaea most similar?

• A. They are prokaryotic and generally lack a membrane-bound nucleus and other membrane-bound organelles.
• B. Their DNA is enclosed within a membrane-bound nucleus.
• C. They reproduce mainly by mitosis and meiosis.
• D. They have cell walls composed primarily of peptidoglycan.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the defining characteristics of the domains Bacteria and Archaea. Both are classified as prokaryotes, meaning their cells do not have a membrane-bound nucleus or membrane-bound organelles.
2. Step 2: Recognize that the DNA in both Bacteria and Archaea is located in a nucleoid region, which is not enclosed by a membrane, distinguishing them from eukaryotes.
3. Step 3: Note that reproduction in these domains occurs mainly through binary fission, a form of asexual reproduction, rather than mitosis or meiosis, which are processes typical of eukaryotic cells.
4. Step 4: Consider the composition of their cell walls. While many bacteria have cell walls made primarily of peptidoglycan, archaea have different cell wall compositions, often lacking peptidoglycan.
5. Step 5: Conclude that the most accurate similarity is that both domains are prokaryotic and generally lack membrane-bound nuclei and organelles, which is a fundamental trait distinguishing them from eukaryotes.