Unicellular organism

Unicellular organism

Valonia ventricosa, a species of algae with a diameter that ranges typically from 1 to 4 centimetres (0.39 to 1.57 in) is among the largest unicellular species

A unicellular organism, also known as a single-celled organism, is an protocells possibly emerging 3.8 billion years ago.[2][3]

colonies, they don't exhibit specialization. These organisms live together, and each cell in the colony is the same. However, each individual cell must carry out all life processes to survive. In contrast, even the simplest multicellular organisms have cells that depend on each other to survive.

All multicellular organisms have a unicellular life-cycle stage. multinucleate, like Myxogastria and Plasmodium.

Candidatus Magnetoglobus multicellularis, related to Deltaproteobacteria, is a multicellular prokaryote. It is neither unicellular, nor a colony.


  • Evolutionary Hypothesis 1
  • Macroscopic Unicellular organisms 2
  • See also 3
  • References 4

Evolutionary Hypothesis

Primitive cells, often referred to as protocells, are the precursors to todays unicellular organisms. Although the

  1. ^ Monad, Biology online, retrieved 2011-06-30 
  2. ^ An Introduction to Cells, ThinkQuest, retrieved 2013-05-30 
  3. ^ a b c Pohorille, Andrew; Deamer, David (6/23/2009). "Self-assembly and function of primitive cell membranes". Research in Microbiology. Retrieved 10/28/2015. 
  4. ^ Coates, Juliet C.; Charrier, Bénédicte (2015-01-01). "Understanding "green" multicellularity: do seaweeds hold the key?". Plant Evolution and Development 5: 737.  
  5. ^ a b Andras, Peter; Andras, Csaba (11/26/2004). "The origins of life – the ‘protein interaction world’ hypothesis: protein interactions were the first form of self-reproducing life and nucleic acids evolved later as memory molecules". Medical Hypotheses. Retrieved 10/28/15. 
  6. ^ a b c "Exploring Life's Origins: Fatty Acids". exploringorigins.org. Retrieved 2015-10-28. 
  7. ^ Max Planck Society Research News Release Accessed 21 May 2009
  8. ^ Researchers Identify Mysterious Life Forms in the Desert. Accessed 2011-10-24.
  9. ^ Bauer, Becky (October 2008). "Gazing Balls in the Sea". All at Sea. Retrieved 27 August 2010. 
  10. ^ John Wesley Tunnell, Ernesto A. Chávez, Kim Withers (2007). Coral reefs of the southern Gulf of Mexico. Texas A&M University Press. p. 91.  
  11. ^ "What is the Largest Biological Cell? (with pictures)". Wisegeek.com. 2014-02-23. Retrieved 2014-03-01. 


See also

Most unicellular organisms are of macroscopic and visible to the naked eye.[7] Examples include:

Macroscopic Unicellular organisms

Amphiphiles have both hydrophobic (water fearing) and hydrophilic (water loving) properties.[3] When amphiphiles like lipids are placed in water, the hydrophobic tails aggregate to form micelles and vesicles, with the hydrophilic ends facing outwards.[6] Primitive cells likely used self-assembling fatty-acid vesicles to separate chemical reactions and the environment.[6] Because of their simplicity and ability to self-assemble in water, it's likely that these simple membranes predated other forms of early biological molecules.[3]

Compartmentalization was necessary for chemical reactions to be more likely as well as to differentiate reactions with the external environment. For example, an early RNA replicase may have replicated other RNA replicases instead of other RNA sequences if not kept separate.[6]

[5] The RNA world hypothesis assumes that RNA molecules could form in abiotic conditions, which would require nucleic acids and ribose to be present. Theoretical and experimental findings show that nucleic acids and sugars could have been synthesized in early prebiotic conditions.[5] Some organisms are partially uni- and multicellular, like

many times in the history of life. independently Additionally, multicellularity appears to have evolved [4]