Structure and Properties of Nucleic Acids

Nota:

• Nucleic acids are the usage for storage and transmission of genetic information. They are biopolymers with high molecular weight.

1. Structure

   Nota:

   • The structure of DNA and RNA is the similar save for several marked differences. DNA have a methy group on one of the Bases (T) While RNA has 2 OH-groups in the sugar.
   1. Components
      1. Base
         1. Purine

            Nota:

            • 2 types: Adenine Guanine 2 ringed structure. One similar to benzene and the other the other ring, hence one delocalized, in the scale, the purines anre longer than the pyrimidines.
         2. Pyrimidines

            Nota:

            • 3 types of pyrimidines. One of it are present in both RNA and DNA while the other 2 are exclusive to their own. Cytosine can be found in DNA and RNA Uracil can be found in RNA While DNA contains Thymine
      2. Sugar
         1. Ribose or 2'-Deoxyribose

            Nota:

            • Ribose is the sugar for RNA 2'-Deoxyribose is the sugar for DNA The Base attach to the sugar at the 1' side.
      3. Phosphate

         Nota:

         • Phosphate join at the 5' site of the sugar and the 3'. They are the "chains" that hold nucleosides together.
      4. Nucleosides

         Nota:

         • Nucleoside: Base + Sugar
   2. DNA

      Nota:

      • A binds with T Adenine with thymineG binds with CGuanine with cytosine A and T have 2 hydrogen bondsA and C have 3 hydrogen bonds
      1. Binding Forces

         Nota:

         • DNA is a polymer made up from inter nucleotide linkages from adjacent nucleotides. 50% of the binding force comes from hydrogen bonds. The other 50% comes from the stacking van der waals forces. GC bonds tend to be stronger than AT due to the extra hydrogen bonds they have Chains have polarity and run antiparallel to each other
      2. Function

         Nota:

         • It can reproduce itself faithfully so that the genetic info is passed from one 'generation' to the next The genes are able to decode itself at any given time.
   3. RNA

      Nota:

      • This one comes from the second step of central dogma. Comes in 3 flavours mRNA: Messenger, template for protein synthesis. tRNA: Adaptor molecule, carry amino acids to generate RNA rRNA: Structural RNA Structurally it is single stranded. and shorter than DNA