In terms of DNA structure and compartment, which statement is accurate?

• A. Eukaryotic DNA is circular and located in the nucleoid.
• B. Eukaryotic DNA is linear and housed in the nucleus, with organelles.
• C. Eukaryotic DNA is linear and located in mitochondria only.
• D. Eukaryotic DNA is circular and located outside membranous boundaries.

Answer: (B)

Eukaryotic DNA is linear and housed in the nucleus, with organelles containing their own DNA. The nuclear genome in eukaryotes is made of linear chromosomes packaged with histones inside a membrane-bound nucleus. In addition, organelles such as mitochondria (and chloroplasts in plants and algae) carry their own circular DNA within their membranes. This combination fits the statement being accurate: the main genome is linear and nuclear, while organellar DNA exists inside membrane-bound compartments.

The other ideas fit more with prokaryotes—circular DNA in a nucleoid without a surrounding membrane—or describe locations outside membranes, which isn’t how eukaryotic DNA is organized.