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Unformatted text preview: NUCLEAR AREA (NUCLEIOD)--- prokaryotic cells do not have a separate, membrane- enclosed area for the DNA. Their DNA, in the form of one circular chromosome without associated histones, is not separated from the cytoplasm. The chromosomes DNA twists into a tight helix and is connected to the plasma membrane. As in eukaryocytes, the chromosome must replicate (make a copy of itself) before the cell divides, so that each daughter cell can receive one. Proteins of the plasma membrane are believed to be responsible for this replication of the DNA. PLASMIDS--not all bacterial cells have these, but many do. Plasmids are small, circular DNA molecules separate from the chromosome. They usually contain 5-100 genes, which code for proteins that may give the cell resistance to certain antibiotics, resistance to toxic metals, ability to produce certain toxins, or ability to synthesize enzymes not included in the chromosomal...
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- Fall '09