RNA is a type of nucleic acid called ribonucleic acid. The RNA nucleotides are joined to form a single strand.

The nucleotides are joined by a bond between the sugar of one nucleotide and the phosphate of the next.

TYPES of RNA                        

  • Messenger RNA (mRNA).
  • This is formed in the nucleus of the cell.
  • It rewrites the sequence of bases of a section of DNA in a process called transcription.
  • mRNA carries the code for building a specific protein from the nucleus to the ribosomes in the cytoplasm. That is, it acts as a messenger.


  • Transfer RNA (tRNA)
  • This is found in the cytoplasm.
  • The tRNA picks up specific amino acids from the cytoplasm and brings them into position on the surface of a ribosome where they can be joined together in specific order to make a specific protein.
  • This process is called translation.


  • Ribosomal RNA (rRNA)
  • These move along an mRNA molecule, and catalyse the assembly of amino acids into protein chains.
  • They also bind tRNAs

mRNA with incorrect codons results in a faulty CFTR protein. But the faulty protein in one mRNA will only affect that specific mRNA strand  – yet the faulty protein is evident in all the epithelial cells! Therefore, the problem must arise when the DNA replicated its errors.