Which of the following is a similarity shared by both the domains Bacteria and Archaea?

• A. Both have peptidoglycan in their cell walls.
• B. Both possess linear chromosomes.
• C. Both lack a membrane-bound nucleus.
• D. Both are capable of photosynthesis.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the characteristics of the domain Bacteria. Bacteria typically have cell walls containing peptidoglycan, possess circular chromosomes, lack a membrane-bound nucleus, and some are capable of photosynthesis.
2. Step 2: Understand the characteristics of the domain Archaea. Archaea do not have peptidoglycan in their cell walls (they have pseudopeptidoglycan or other polymers), possess circular chromosomes, lack a membrane-bound nucleus, and generally are not photosynthetic.
3. Step 3: Compare the options given with the known characteristics of both domains. Identify which feature is common to both Bacteria and Archaea.
4. Step 4: Analyze each option: (a) Peptidoglycan is unique to Bacteria, not Archaea; (b) Both have circular, not linear, chromosomes; (c) Both lack a membrane-bound nucleus, making this a shared feature; (d) Photosynthesis is common in some Bacteria but not in Archaea.
5. Step 5: Conclude that the similarity shared by both domains is the absence of a membrane-bound nucleus, which is a defining feature of prokaryotes.