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.
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 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.
- 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.
- 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.
- 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.