Prokaryotes have circular single or double?

[hunterpostbacst]

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Some books said that prokaryotes have single circular DNA but the others said that they have a circular double stranded DNA. Anyone can clarify this?

 

[Dent010]

Prokaryotes have a single circular chromosome called a plasmid
.

 

[hunterpostbacst]

Prokaryotes have a single circular chromosome called a plasmid.

Isn't plasmid only in virus? Prokaryotes are mostly called bacteria, not virus. Isn't it?

 

[Dent010]

from wikipedia: "In prokaryotes, a small circular DNA molecule may be called either a plasmid or a small chromosome."

 

[cmills66]

Bacteria have a single circular chromosome called a plasmid, which has a single origin of replication, and is double stranded DNA not enclosed within a nucleus (called the nucleoid region i think)

 

[bennijai]

Plasmids are double stranded DNA, not single stranded. If you guys can recall DNA recombination with plasmid vectors, the restriction enzymes cuts the plasmid into sticky ends.

If you mean single as in how many present, then usually just one plasmid present in the bacteria cell.

 

[doctor K]

Some books said that prokaryotes have single circular DNA but the others said that they have a circular double stranded DNA. Anyone can clarify this?

single circular DNA = one circular double stranded DNA
a circular double stranded DNA = one circular double stranded DNA

So they basically mean the same thing, IMO. 🙂

 

[navneetdh]

they have a 1 circular double starnded DNA plus 1 circular double stranded plasmid.

Viruses do not have plasmids. They only have DNA or RNA