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Explainabout thetypes ofRNA molecules . |
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Answer» Solution :(i) Ribonucleicacids aresimilarto DNA. CELLS contain upto eight times high QUANTITY of RNA than DNA . RNA is foundin largeamountin the cytoplasm anda lesser amountin thenucelus. (ii) RNA molecules are classifiedaccording to theirstructureand function intothree majortypes. (a) Ribosomal RNA (r-RNA) . (b)Messenger RNA (m-RNA) . (C) Transfer RNA (t-RNA). (III) r-RNA : r-RNA is mainly found in cytoplasmand in ribosomes , which contain 60% RNA and 40% protein. Ribosomer arethe sitesat whichprotein synthesis takes place. (iv) t - RNA :t - RNAmolecules havelowestmolecular weightof all nucleicacids. Theyconsistof 73-94 nucleotides in a single chain . The funtionof t - RNA is to carry amino acids to thesitesof protein synthesis on ribosomes. (v) m - RNA : - RNA is presentin small quanity andveryshort lived . They are singlestranded and their synthesis take place on DNA. The synthesis m - RNA from DNA strandis calledtranscription . m - RNA carriesgeneticinformationfor DNA to theribosomers for proteinsythesis. |
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