NEET BIOLOGY

Detailed explanation-1: -A plasmid is a small circular DNA molecule found in bacteria and some other microscopic organisms. Plasmids are physically separate from chromosomal DNA and replicate independently.

Detailed explanation-2: -While most prokaryotes, like E. coli, contain a single circular DNA molecule that makes up their entire genome, recent studies have indicated that some prokaryotes contain as many as four linear or circular chromosomes. For example, Vibrio cholerae, the bacteria that causes cholera, contains two circular chromosomes.

Detailed explanation-3: -The DNA of most bacteria is contained in a single circular molecule, called the bacterial chromosome. The chromosome, along with several proteins and RNA molecules, forms an irregularly shaped structure called the nucleoid.

Detailed explanation-4: -Linear DNA is seen in the nucleus of eukaryotic organisms. Circular DNA is seen in the cytoplasm of prokaryotic cells, organelles like chloroplast and mitochondria.

Detailed explanation-5: -In many bacteria the DNA is present as a single circular chromosome, although some bacteria may contain two chromosomes, and in some cases the DNA is linear rather than circular. A variable number of smaller, usually circular (though sometimes linear) DNA molecules, called plasmids, can carry auxiliary information.