Daily Newsletter January 18, 2012
Today's Topic: Nucleic Acids
Today we turn our attention to the basic structure of nucleic acids. We are talking about Ribonucleic Acids and Deoxyribonucleic Acids. The two critical concepts to master today are the general structure of nucleotides (monomers of nucleic acids) and the concept of base complementarity.
Nucleotide Structure:
The following image from wikipedia's image gallery shows the basic structure of the nucleotide and the five nitrogenous bases.
As with amino acids, the nucleotide contains a functional group: the nitrogenous base. Just like the side chain in an amino acid, the nitrogenous base will play an important part in the function of this biomolecule. The Sugar-Phosphate then becomes the backbone of the molecule (line the Amino-Chiral Carbon-Carboxyl of an amino acid). We will in later weeks that the sugar-phosphates of nucleotides will create the strands of DNA and RNA. The nitrogenous bases then playing an information role.
Base Complementarity:
The nucleic acids are referred to as informational biomolecules (biopolymers). This is because the sequence of nucleotides carries information on how to build RNA and Proteins. One of the central foundations of genetics (i.e., how it all works), is base complementarity. Here we are looking at the interactions between purines and pyrimidines:
A links with T through 2 hydrogen bonds.
G links with C through 3 hydrogen bonds.
A to T G to C
U has the binding properties of T, but is only found in RNA.
T is never found in RNA, only DNA.
Daily Challenge:
Review the history of the discovery of DNA. When did people first suspect that DNA was the molecule of inheritance? Who figured out the structure of DNA? Who figured out how DNA was replicated?
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