Sonia

UNICELLULAR ORGANISMS

Unicellular organisms are organisms that only have one cell. They are divided into two quite different types, from different classification kingdoms.

 The prokaryotes, bacteria and archaea, have cells with no nucleus and a simple cell structure.

 Eukaryotes have a nucleus, and a more complex cell structure.

The differences between the prokaryota and eukaryota are significant. Eukaryotes possess a nucleus, while prokaryotes lack it, and eukaryotes possess a range of subcellular organs called organelles, which prokaryotes do not.

PARAMOECIUM:

paramecium (parəmē`sĭəm), unicellular organism of the genus Paramecium, of the ciliate phylum Ciliophora Ciliophora , phylum in the kingdom Protista consisting of the ciliates, or ciliophores, complex freshwater or saltwater protozoans that swim by the coordinated beating of their cilia—short, hairlike structures that cover the cell surface. found in freshwater throughout the world. Like other protozoans protozoan , informal term for the unicellular heterotrophs of the kingdom Protista. Protozoans comprise a large, diverse assortment of microscopic or near-microscopic organisms that live as single cells or in simple colonies and that show no differentiation int, paramecia, previously considered one-celled animals, are now customarily placed in kingdom Protista Protista or Protoctista , in the five-kingdom system of classification, a kingdom comprising a variety of unicellular and some simple multinuclear and multicellular eukaryotic organisms.The paramecium has a stiff outer covering that gives it a permanent slipper shape. It swims rapidly by coordinated wavelike beats of its many cilia—short, hairlike projections of the cell. A paramecium normally moves forward in a corkscrew fashion but is capable of reversing direction when it encounters adverse conditions. This trial-and-error behavior (backing up and then continuing forward in a slightly different direction until an optimum path is...