Plasmid - Research Article from Macmillan Science Library: Genetics

This encyclopedia article consists of approximately 4 pages of information about Plasmid.
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Types of Plasmids

Plasmids are not usually required by their host cell for its survival. Instead, they carry genes that confer a selective advantage on their host, such as resistance to heavy metals or resistance to naturally made antibiotics carried by other organisms. Alternatively, they may produce antibiotics (toxins) that help the host to compete for food or space. For instance, antibiotic resistance genes produced by a plasmid will allow its host bacteria to grow even in the presence of competing bacteria or fungi that produce these antibiotics.

Plasmids are subgrouped into five main types based on phenotypic function. R plasmids carry genes encoding resistance to antibiotics. Col plasmids confer on their host the ability to produce antibacterial polypeptides called bacteriocins that are often lethal to closely related or other bacteria. The col proteins of E. coli are encoded by plasmids such as ColE1. F plasmids contain the F...

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This section contains 1,133 words
(approx. 4 pages at 300 words per page)
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Macmillan Science Library: Genetics
Plasmid from Macmillan Science Library: Genetics. Copyright © 2001-2006 by Macmillan Reference USA, an imprint of the Gale Group. All rights reserved.
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