Extrachromosomal DNA membrane bound nucleus like the eukaryotes, they do contain a nucleoid region in which the main chromosome is found. Extrachromosomal DNA exists in prokaryotes outside the nucleoid region as circular or linear plasmids. Bacterial plasmids are typically short sequences, consisting of 1 kilobase (kb) to a few hundred kb segments, and contain an origin of replication which allows the plasmid to replicate independently of the bacterial chromosome. The total number of a particular plasmid within a cell is referred to as the copy number and can range from as few as two copies per cell to as many as several
Hürthle cell cells with distinct cell borders. The cytoplasm of the oncocytes in Hürthle cell adenomas and carcinomas is characterized by an eosinophilic granular nature, which is commonly due to the oncocytes' high content of mitochondria. Some of these cells can contain up to 5,000 mitochondria, which fills the cytoplasm to the point of nearly excluding other organelles. This high amount of mitochondria is reported to be a result of mutations in the mitochondrial DNA. Some scientists have identified these mutations as deletions in the mitochondrial DNA of Hürthle cells found in neoplasms and Hashimoto's thyroiditis. Hürthle cell cancer can be separated