Nucleus+Period+4



Nucleus Information-  - The nucleus is a membrane-enclosed organelle that is found in all eukaryotic cells. - It holds most of the cells genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. - The main function or purpose of the nucleus is to maintain the integrity of these genes and control the activities of the cell by regulating gene expression. -There are two membranes around the nucleus, each membrane is a lipid bilayer with associated proteins. -One of the main structures making up the nucleus is the nuclear lamina, a meshwork within the nucleus, that adds mechanical support, like the cytoskeleton supports the cell as a whole. Interesting facts- - The nuclear membrane has pores allowing the movement of substances through it. - The nuclear membrane joins up with the endoplasmic reticulum. - The nucleus contains genes that hold the information needed to make proteins. - If the nucleus of a cell is removed, the cell cannot survive. - The nuclear envelope separates the nucleus from the rest of the cell. Disorders- Mononucleosis: - The virus can stay alive within the body for several months. The name mononucleosis comes from the fact that the disease distorts the white blood cells, causing them to only have one nucleus. Only a blood test called the mononucleosis spot test can determine if someone has the disease.

http://www.rockefeller.edu/labheads/rout/images/yeast_nucleus.jpg http://spectorlab.cshl.edu/images/NucleusModel.jpg

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