Give an account of RNA and its role in protein sythesis.

RNA is a single stranded molecule, composed of a ribose sugar phosphate backbone (as opposed to the deoxyribose sugar phosphate double-stranded DNA) and the bases, adenine, guanine, cytosine and uracil (instead of thymine). RNA plays an important role in DNA transcription and translation into the final protein:
Transcription - mRNAA specific gene on DNA is transcribed into a complimentary copy by the enzyme, RNA polymerase, using RNA bases. This copy is known as the mRNA primary transcript. The mRNA goes through several processing steps, for example, mRNA splicing, whereby non-coding 'exons' are removed and coding 'introns' are kept to form the final, mature mRNA transcript. This transcript exits the nucleus via a nuclear pore and enters the cytoplasm.
Translation - tRNA and rRNAIn the cytoplasm, the mRNA goes to the ribosome, an organelle made of another form of RNA, rRNA and some protein subunits. The ribosome is the site of protein translation. tRNA acts to collect the amino acids corresponding to each 3 base codon on the mRNA. tRNA has an amino acid attachment site and an anticodon, an exposed codon which pairs with a codon on the mRNA, allowing correct placement of the specific amino acid along the polypeptide chain. Translation proceeds, each amino acid getting added by tRNAs which are recycled when they detach, until the stop codon is reached. At this point, the polypeptide is released from the ribosome and folds into its native state.