Unicellular Organisms

Unicellular Organisms

 

(also unicellulars), plant or animal organisms consisting of a single cell. There are two levels of organization among unicellular organisms: prokaryotic and eukaryotic. Prokaryotic unicellulars (bacteria and some blue-green algae) lack a differentiated nucleus and do not undergo mitosis; a nucleoid contains the apparatus for the process of genetic information. Eukaryotic unicelluar organisms (green and some other algae; among animals, protozoans) have a cell nucleus that divides by mitosis. Unicellulars resemble the cells of multicellular organisms in general structure and contain a similar set of organelles. Among unicellulars, there is varying complexity of morphological differentiation, from very simply arranged organisms (amoebas, chlorellas) to extremely complex ones (infusorians, Acetabularia). Unicelluar organisms may form colonies. (See alsoMULTICELLULAR ORGANISMS.)

References in periodicals archive ?
Microalgae are unicellular organisms that are usually found in freshwater and marine systems, and are capable of performing photosynthesis, Al Harethi said.
Silab's historic understanding of the plant world has been supplemented by unique expertise related to the production and use of unicellular organisms made using biotechnologies.
In particular, this project will apply surface enhanced spectroscopic methods to characterise eco-corona composition and evolution and how this affects ENM interactions with, and impact upon unicellular organisms.
The application of unicellular organisms to study the toxic effects of pesticides from contaminated wastewater is relatively new throughout the world.
In reality, a lot of the oil and gas that we have in Alberta comes from algae and other unicellular organisms that were living in oceans.
We don't know what it does in unicellular organisms, but we can now place the origin of genes that are associated with multicellularity in unicellular organisms.
Here neurologists and other biomedical researchers explain in some detail how PAKs--particularly the oncogenic kinases PAK1 and PAK4 and their blockers--may control various aspects of life and health, and how mammalian PAKs have functionally evolved from their ancestral origins in unicellular organisms such as yeast and amoebas through a series of mutations over millions of years.
Alexander Rohrbach und Matthias Koch created a kind of light tube that traps the agile unicellular organisms.
Another theory is that the fossils are protists, which are unicellular organisms lacking a definite cellular arrangement.
In 1905, Konstantin Mereschkowski postulated that chloroplasts arose by cells incorporating green photosynthetic unicellular organisms.
A PAPER IN the January/February Journal of Eukaryotic Microbiology dispels "the myths of intelligent design" by examining the evolution of amoebas and other unicellular organisms.
After Gram staining, gram-positive spherical unicellular organisms were observed (Figure).