What Are Nucleotides & Nucleic Acids? - P3
Ribonucleic Acids (RNA)
In living organisms, 
RNA is a single stranded nucleic acid molecule. In viruses, non-living infectious particles, RNA can be single or double stranded.

There are four different types of nitrogenous bases found in an RNA molecule: adenine (A), guanine (G), cytosine (C) and uracil (U). In RNA, uracil takes the place of the thymine found in DNA.

When RNA bases are laid down to build an RNA molecule, DNA is unzipped, and the new RNA molecule made is compliment of the DNA template. 
For example, if the DNA strand has the following bases, in this order, ATTGCACT, the new RNA molecule being made will have the base sequence UAACGUGA. 

Genetic information copied from DNA is used to build three types of RNA:
  • Ribosomal RNA (rRNA)
  • Messenger RNA (mRNA)
  • Transfer RNA (tRNA)

Ribosomal RNA - The Protein Factories: Most of the RNA in cells is part of the structure of small cellular organelles known as ribosomes, the protein factories of the cells.

Messenger RNA - The Genetic Blueprint: Messenger RNA is a copy of the genetic information that was transcribed from the cell’s original blueprint, DNA. This copy of the genetic information is brought to the ribosome and used as instructions for building proteins.
Image Comparing DNA and RNA Structure
To learn more about molecular genetics and biochemistry see the following animations and SPO Class Note Articles:

Nucleic Acid & Nucleotide Animations
  • DNA: The Double Helix - Explore DNA structure using the Molecular Workbench software, from The Concord Consortium.

Class Notes & Lecture Materials

  • Bauman, R. (2014) Microbiology with Diseases by Taxonomy, 4th ed., Pearson Benjamin Cummings.
  • Park Talaro, K. (2008) Foundations in Microbiology, McGraw-Hill.
  • Campbell, N. & Reece, J. (2002) Biology, 6th Edition, Benjamin Cummings.

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Ribosome building a protein with the help of RNA.
Transfer RNA - The Amino Acid Suppliers: Transfer RNA is also part of the process of building proteins. Like a little truck, tRNA brings the amino acid to the ribosome. Which amino acid it brings depends on which was coded for in the mRNA instructions. At the ribosome, these amino acids are joined together to form proteins.

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