Organelles

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Organelles are separate compartments in eukaryotic cells that contain different enzymes and molecules and have specific roles in maintaining cell structure and function [1]. Each organelle has its own membrane in the form of a lipid bilayer, this allows compartmentalization and segragation of different chemical activites. Different organelles can be seperated by centrifugation due to thier varying densities.

Eukaryotic Organelles and their Functions:

  • Ribosomes - host sites for protein synthesis: translation of mRNA into proteins.
  • Nucleus - contains chromosomes as a store of genetic information.
  • Nuclear envelope - surrounds the nucleus, allows passage of material into and out of the nucleus. Eg mRNA 
  • Rough ER (endoplasmic reticulum) - located next to the nucleus, the rough ER has docked ribosomes for protein synthesis. 
  • Smooth ER - endoplasmic reticulum without docked ribosomes - synthesis of lipids and steroids
  • Lysozyme - contain hydrolytic enzyme for intracellular degredation
  • Endosomes - sort endocytosed materials
  • Golgi Body - post-transcriptional modification, separation and assortment of newly synthesised proteins
  • Peroxisomes - contain enzymes for oxidation of toxins

References

  1. Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P. 2008. Molecular Biology of the Cell. 5th Edition. p695. Garland Science, New York