Biology, asked by saurabhmittal9792, 1 year ago

Mention the main function of circular DNA found in bacterium cell.

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Answered by fuggy96
1
Bacterial DNA

Bacteria have a single circular chromosome that is located in the cytoplasm in a structure called the nucleoid. Bacteria also contain smaller circular DNA molecules called plasmids.

Bacterial DNA – a circular chromosome plus plasmids

The DNA of most bacteria is contained in a single circular molecule, called the bacterial chromosome. The chromosome, along with several proteins and RNAmolecules, forms an irregularly shaped structure called the nucleoid. This sits in the cytoplasm of the bacterial cell.

In addition to the chromosome, bacteria often contain plasmids – small circular DNA molecules. Bacteria can pick up new plasmids from other bacterial cells (during conjugation) or from the environment. They can also readily lose them – for instance, when a bacterium divides in two, one of the daughter cells might miss out on getting a plasmid.

Every plasmid has its own ‘origin of replication’ – a stretch of DNA that ensures it gets replicated (copied) by the host bacterium. For this reason, plasmids can copy themselves independently of the bacterial chromosome, so there can be many copies of a plasmid – even hundreds – within one bacterial cell.

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