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Eukaryotes are considerably more complicated than prokaryotes (KingdomMonera?).

Each cell has at least one nucleus, a structure where the DNA is stored bound by a double membrane. Generally there is more than one ChromoSome?, and there are usually multiple copies of the same genes. Nuclei divide through a process called NuclearMitosis?, where microtubules pull apart the divided chromosomes and ensure each daughter has a full set.

Many eukaryotes also undergo a process of SexualReproduction?. This involves two phases: SynGamy?, where two haploid (single gene set) cells fuse to form a diploid, and NuclearMeiosis?, a process similar to mitosis where the chromosomes are divided to form haploids. The role of haploid and diploid stages in the life cycle varies considerably.

There are a wide variety of intracellular organelles. These include membrane bound structures, notably EndoplasmicReticulum? and various-purposed vacuoles. Nearly all eukaryotes have MitoChondria? to burn food, and quite a few have ChloroPlasts? for photosynthesis; these appear to actually be reduced endosymbiont bacteria.

Multicellular organization has arisen among the eukaryotes a number of times. Of such forms, the KingdomAnimalia, KingdomPlantae?, and KingdomFungi? are typically listed separately as top-level taxa. Other groups are left in the junk-basket category of KingdomProtista. These include the following:

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Last edited January 23, 2001 1:04 pm by JoshuaGrosse (diff)