| MadSci Network: Cell Biology |
Your predictions are quite accurate! In a eukaryotic cell (such as a nucleated one that would be found in a mammal) the largest organelle would indeed be the nucleus, which usually have a diameter of several microns (=micrometers, µm). To give you an idea of the size, if you shrank yourself and the world so that it was the size of a soccer ball, then a normal-sized nucleus would seem to be several hundreds of meters across, about the size of a large stadium in your miniature world! In a non-nucleated mammalian cell such as a red blood cell, the largest organelles would probably be mitochondria, which are 0.5-1 microns. The smallest organelle is, as you have guessed correctly, the ribosome, which is only about 20 nanometers (= 0.02 microns) in size. From your miniature world the size of a soccer ball, a normal sized ribosome would seem to be about the size of a large television! I hope that helps. Good luck in your studies, and please follow these links for further information on cell structure and organelles. http://en.wikipedia.org/wiki/Cell_(biology) http://www.cs.stedwards.edu/chem/Chemistry/CHEM43/CHEM43/Ribosomes/Ribosome.HTML Moderator's note: The largest organelle in a plant cell might not be the nucleus, but is instead a large, fluid filled vacuole. Chloroplasts can also be quite large in some plant cells, such as those on the leaves actively undergoing photosynthesis. http://www.biologymad.com/cells/ultrastructure.htm http://sps.k12.ar.us/massengale/cell_functions.htm
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