Which feature distinguishes prokaryotes from eukaryotes?

Which feature distinguishes prokaryotes from eukaryotes?

• A. Absence of membrane-bound organelles
• B. Presence of mitochondria
• C. Linear DNA in nucleus
• D. Multicellularity

Answer: (A)

The key idea is how cells organize their internal space. Prokaryotes do not have membrane-bound compartments inside the cell, including a true nucleus; their genetic material sits in a nucleoid region rather than inside a membrane. Eukaryotes, in contrast, have several membrane-bound organelles, with a defined nucleus that houses linear DNA and other organelles like mitochondria. That fundamental difference in cellular organization is what sets prokaryotes apart from eukaryotes. Absence of membrane-bound organelles is the clearest universal marker. Every prokaryote lacks these compartments, while every eukaryote has them. The other statements touch on true features of many eukaryotes—such as having mitochondria or linear DNA in a nucleus—and some edge or exception cases exist (like bacteria with unusual chromosome structures or eukaryotes with mitochondrial-derived organelles), so they’re not as universally distinguishing. Multicellularity is not reliable either, since many organisms can be unicellular or multicellular across both domains.

The key idea is how cells organize their internal space. Prokaryotes do not have membrane-bound compartments inside the cell, including a true nucleus; their genetic material sits in a nucleoid region rather than inside a membrane. Eukaryotes, in contrast, have several membrane-bound organelles, with a defined nucleus that houses linear DNA and other organelles like mitochondria. That fundamental difference in cellular organization is what sets prokaryotes apart from eukaryotes.

Absence of membrane-bound organelles is the clearest universal marker. Every prokaryote lacks these compartments, while every eukaryote has them. The other statements touch on true features of many eukaryotes—such as having mitochondria or linear DNA in a nucleus—and some edge or exception cases exist (like bacteria with unusual chromosome structures or eukaryotes with mitochondrial-derived organelles), so they’re not as universally distinguishing. Multicellularity is not reliable either, since many organisms can be unicellular or multicellular across both domains.