What is the key difference between prokaryotic and eukaryotic cells regarding nucleus and membrane-bound organelles?

What is the key difference between prokaryotic and eukaryotic cells regarding nucleus and membrane-bound organelles?

• A. Prokaryotes have a nucleus; eukaryotes do not
• B. Prokaryotes lack a true nucleus and most membrane-bound organelles; eukaryotes have a nucleus and membrane-bound organelles
• C. Both have a nucleus; only size differs
• D. Eukaryotes lack mitochondria; prokaryotes have mitochondria

Answer: (B)

Understanding how cells organize their genetic material and internal compartments is essential. Prokaryotic cells do not have a true nucleus; their DNA sits in a nucleoid region that is not membrane-bound. They also lack membrane-bound organelles such as mitochondria or a endoplasmic reticulum. Eukaryotic cells, in contrast, have a defined nucleus enclosed by a nuclear envelope that houses their DNA, and they contain multiple membrane-bound organelles that compartmentalize different cellular processes. This combination—no true nucleus and no membrane-bound organelles in prokaryotes versus a nucleus plus membrane-bound organelles in eukaryotes—is why the statement is correct. The other options contradict what we know about cell structure: prokaryotes do not have a nucleus, eukaryotes do have mitochondria, and not all prokaryotes possess mitochondria.

Understanding how cells organize their genetic material and internal compartments is essential. Prokaryotic cells do not have a true nucleus; their DNA sits in a nucleoid region that is not membrane-bound. They also lack membrane-bound organelles such as mitochondria or a endoplasmic reticulum. Eukaryotic cells, in contrast, have a defined nucleus enclosed by a nuclear envelope that houses their DNA, and they contain multiple membrane-bound organelles that compartmentalize different cellular processes. This combination—no true nucleus and no membrane-bound organelles in prokaryotes versus a nucleus plus membrane-bound organelles in eukaryotes—is why the statement is correct. The other options contradict what we know about cell structure: prokaryotes do not have a nucleus, eukaryotes do have mitochondria, and not all prokaryotes possess mitochondria.