Kamis, 07 November 2013

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RNA Structure And RNA Type

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RNA  is a genetic material  found  in certain virus  (RNA virus),  cells and molecules  that  leads to protein synthesis.  In virus, RNA molecule leads to protein synthesis  process (virus protein coat formation)  and replication  (RNA duplication  process).


The structure  of RNA. (a) Computer  model  of RNA polynucleotide  and  (b) RNA nucleotide.


RNA Structure

The model of RNA structure is almost the same as that of DNA. Each nucleotide is built by one molecule of pentose sugar, one group of Phosphate and one off our types of nitrogen base. The differences are the Pentose sugar in RNA is ribose instead of deoxyribose, the nitrogen base in RNA is uracil (U)  instead  of thymine  (T), and RNA is built by single- Stranded polynucleotide chain instead of double-stranded in DNA.

RNA Type

RNA  types.  (a) Base  triplet of  tRNA anticodon  pair with (b) triplet of mRNA  codon.

The followings are the three types of RNA that will be produced
Whenever they are required.

  1. Ribosomal RNA (rRNA). The rRNA is printed by DNA in nucleus. Ribosomal RNA together with protein reside cytoplasm is set into sub- unit of ribosome. Ribosomal RNA catalyzes the attachment of codon and anticodon  in ribosome.
  2. Transfer RNA (tRNA). Transfer RNA is printed by DNA in nucleus.  It is necessary  to transport amino acid  from cytoplasm  toward  ribosome. The tRNA is a single-strand that folds backward so that some strands pair and some others bend. At one end of the  fold strand  there is base triplet called  anticodon.  Anticodon triplet will pair with codon triplet in mRNA. Another strand end which is called the 3' end functions as the attachment site of amino  acid.
  3. Messenger RNA (wRNA).  Messenger RNA is transcribed from DNA in nucleus and carries genetic blueprint  that is copied according  to Nitrogen base sequence in DNA strand. Genetic blueprint consists of three nucleotide bases called codon. The codon will determine amino acid sequence  in protein.
source: biology, 2001

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