The nucleus
Organelles are specialized membrane-enclosed structures in the cytoplasm of eukaryotic cells. The nucleus, which contains DNA in the form of chromosomes, is the most characteristic eukaryotic organelle. The nuclear envelope is connected to a system of membranes in the; cytoplasm called the endoplasmic reticulum (ER). In addition to the nucleus, eukaryotic cells may contain several other types of organelles, which may include mitochondria, chloroplasts, the endoplasmic reticulum, the Golgi apparatus, and lysosomes. Each of these organelles performs a specific function critical to the cell's survival. Recall that DNA contains the information required to build cellular proteins. In eukaryotic cells, the membrane that surrounds the nucleus — commonly called the nuclear envelope — partitions this DNA from the cell's protein synthesis machinery, which is located in the cytoplasm. Eukaryotic cells contain much more DNA than do bacteria, and this DNA is organized as multiple chromosomes located within a nucleus. b. The nucleus (def) in eukaryotic cells is separated from the cytoplasm by a nuclear envelope (nuclear membrane) (see Fig. 32). a. The Nucleus Fundamental Statements for this Learning Object: 1. Eukaryotic cells contain much more DNA than do bacteria, and this DNA is organized as multiple chromosomes located within a nucleus. 2. The nucleus in eukaryotic cells is separated from the cytoplasm by a nuclear envelope. 3. The presence of a nucleus gives eukaryotes their name, which comes from the Greek ευ (eu, well) and κάρυον (karyon, nut or kernel). Eukaryotic cells also contain other membrane-bound organelles such as mitochondria and the Golgi apparatus. In addition, plants and algae contain chloroplasts. Eukaryotic organisms may be unicellular, or multicellular. Only eukaryotes have many kinds of tissue made up of different cell types. Eukaryotic cells are typically much larger than those of prokaryotes. They have a variety of internal membrane-bound structures, called organelles, and a cytoskeleton composed of microtubules, microfilaments, and intermediate filaments, which play an important role in defining the cell's organization and shape. Prokaryotic and eukaryotic cells differ a great detail in both the amount and the organization of their molecules of DNA. a. Eukaryotic cells contain much more DNA than do bacteria, and this DNA is organized as multiple chromosomes located within a nucleus. b. The nucleus (def) in eukaryotic cells is separated from the cytoplasm by a nuclear envelope (nuclear membrane) (see Fig. 32).  The defining feature that sets eukaryotic cells apart from prokaryotic cells (Bacteria and Archaea) is that they have membrane-bound organelles, especially the nucleus, which contains the genetic material, and is enclosed by the nuclear envelope. Eukaryotic cells are typically much larger than those of prokaryotes. They have a variety of internal membrane-bound structures, called organelles, and a cytoskeleton composed of microtubules, microfilaments, and intermediate filaments, which play an important role in defining the cell's organization and shape. In eukaryotes, however, the DNA takes the form of compact chromosomes separated from the rest of the cell by a nuclear membrane (also called a nuclear envelope). Eukaryotic cells also contain a variety of structures and organelles not present in prokaryotic cells. Recall that DNA contains the information required to build cellular proteins. In eukaryotic cells, the membrane that surrounds the nucleus — commonly called the nuclear envelope — partitions this DNA from the cell's protein synthesis machinery, which is located in the cytoplasm. Prokaryotic Cell Structure. Prokaryotic cells are not as complex as eukaryotic cells. They have no true nucleus as the DNA is not contained within a membrane or separated from the rest of the cell, but is coiled up in a region of the cytoplasm called the nucleoid. Prokaryotic organisms have varying cell shapes
http://classes.midlandstech.edu/carterp/Courses/bio225/chap04/lecture6.htm http://www.nature.com/scitable/topicpage/eukaryotic-cells-14023963 http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit4/eustruct/nuceu.html https://en.wikipedia.org/wiki/Eukaryote http://faculty.ccbcmd.edu/~gkaiser/biotutorials/eustruct/nuceu.html https://en.wikipedia.org/wiki/Eukaryote http://www.nature.com/scitable/topicpage/eukaryotic-cells-14023963 http://biology.about.com/od/cellanatomy/ss/prokaryotes.htm
what eukaryotic cell structure contains DNA