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Miss_Naqvi Friday, December 22, 2006 11:04 PM

R.n.a
 
[B][COLOR="blue"][SIZE="4"]RNA Ribonucleic acid.[/SIZE][/COLOR][/B]

[center][img]http://academic.brooklyn.cuny.edu/biology/bio4fv/page/molecular%20biology/rna-structure.jpg[/img]

[img]http://www.biologycorner.com/resources/mRNA-colored.gif[/img][/center]

RNA is similar to DNA except:

[COLOR="Blue"][B]1. has on strand instead of two strands.

2. has uracil instead of thymine

3. has ribose instead of deoxyribose[/B][/COLOR]

[center][img]http://www.biologycorner.com/resources/DNA-RNA.gif[/img][/center]

mRNA has the job of taking the message from the DNA to the nucleus to the ribosomes.

[B][COLOR="Purple"]Transcription[/COLOR][/B] - RNA is made from DNA

[B][COLOR="purple"]Translation[/COLOR][/B] - Proteins are made from the message on the RNA

[center][img]http://www.biologycorner.com/resources/transcription-translation.gif[/img][/center]

[COLOR="DarkOrange"][B]RNA is composed of the sugar ribose rather than deoxyribose, and one of the four nucleotide bases is different. The adaptor molecules convert the nucleotide [U]'language' of RNA into [/U]the amino acid [U]'language' of proteins[/U]. The RNA base Uracil functions as if it were the DNA base Thymine. So, as expected, DNA base C pairs with RNA base G and DNA base T pairs with RNA base A, but DNA base A pairs with RNA base U. The 'language conversion' process of protein synthesis is also known as translation. [/B][/COLOR]


[COLOR="DimGray"]When translation completes, RNA molecules move out of the nucleus and enters into the main body of the cell. Here, the RNA base sequence is 'read' in groups of 3 (eg UUC, ACG) that correspond to bases in the cell, which represent amino acid molecules. When these groups of amino acids connect they become proteins that build, maintain and manage specific cellular activities. This process is called [/COLOR][B][COLOR="DarkRed"]protein synthesis[/COLOR][/B].


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