Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso


  • Felipe Gomez
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_1122-2


An organelle is a specialized subunit inside a cell. It is separated from the surrounding cytoplasmic media by a lipid bilayer and plays a particular role or function within the cell similar to that of organs in an animal’s body. The absence of a nucleus, a membrane-enclosed organelle containing the genome, is one of the major features that differentiate prokaryotes from eukaryotes. The most notable examples of organelles are those involved in energy transduction reactions in eukaryotes which were originated by endosymbiont bacteria: chloroplasts present in plants cells, algae and some protists which are responsible for photosynthesis, and mitochondria in almost all eukaryotes where respirationfor energy production takes place. Other important organelles are hydrogenosomes involved in energy generation in anaerobic conditions; the endoplasmic reticulum responsible for many functions, including the synthesis of new membrane material; lysosomes involved in protein...


Endoplasmic Reticulum Anaerobic Condition Lipid Bilayer Cell Movement Protein Degradation 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Centro de Astrobiología (CSIC/INTA)Instituto Nacional de Técnica AeroespacialTorrejón de Ardoz, MadridSpain