I’ve always learned that Prokaryotic organisms have no nuecleus. I’ve also been told that the DNA is held in the nucleus.
So does no nucleus mean no DNA? But then how would they reproduce asexually?
-P.K.
Prokaryote is defined in my dictionary as "An organism of the kingdom Prokaryotae, constituting the bacteria and cyanobacteria, characterized by the absence of a nuclear membrane and by DNA that is not organized into chromosomes."
I do not know about the scheme of reproduction.
Although the DNA is not organized and contained in a nucleus, it does reside in specific areas of the cell, called a nuclear region.
So, Prokaryotes DO have DNA. They rep[roduce mainly by binary fission, which means the DNA divides, and then migrate to separate parts of the cell, which then divides into two. Since Prokaryotes have few organelles, their division is very simple. Proks can also engage in conjugation, which is when two proks combine together, mix their DNA, and then separate. The Proks then undergo fission twice, so there are 4 of each new Prok with the new DNA combinations. (if anyone has a link that says the divdes twice thing, it would be much appreciated, i’ve gone through 40- sites that only gloss over conjugation)
here is a neat-o site with cool pictures (well, cool if you are a micro-bio nerd like me!):
http://gened.emc.maricopa.edu/bio/bio181/BIOBK/BioBookmito.html#Prokaryotic%20Cell%20Division
here is E. coli with a conjugation pilus: http://www.cat.cc.md.us/courses/bio141/lecguide/unit1/prostruct/dksexpil.html
a pilus is what the bacteria use in conjugation and to attach to surfaces, the conjugation pilus is also referred to as an F factor or a Sex factor. Bacts lose and create pili all their lives, and can even change the tips depending on what they need to do (sort of like those multi-head screwdrivers)