BIOLOGICAL CLASSIFICATION
KINGDOM MONERA
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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can be circular as well as linear within the same cell
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are always circular
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are always linear
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can be either circular of linear, but never both within the same cell
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Detailed explanation-1: -Solution : Prokaryotic cells contain their chromosome as circular entity. Usually the entire genome is a single molecule of circular DNA but often the number may vary upto three.
Detailed explanation-2: -Not all bacterial chromosomes are circular. There are several genera of bacteria in which linear chromosomes are common, including Borrelia, Streptomyces, and Agrobacteria.
Detailed explanation-3: -Since bacteria are haploid, that is they have only one chromosome and only reproduce asexually, there is also no meiosis in bacteria. The bacterial chromosome is one long, single molecule of double stranded, helical, supercoiled DNA.
Detailed explanation-4: -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-5: -The circular concept of the bacterial chromosome was based initially on experiments involving conjugation mapping and autoradiographic imaging of DNA. This view was then supported by DNA fragment mapping, genome sequencing, and the analysis of linear DNA produced by a single cleavage of chromosomal DNA.