DNA and RNA

I. Introduction
   
II. History
   
     A. Johann Friedrich Miescher (1844-1895)
   
          1. Nuclein (1860s)
   
          2. Nucleic Acid (today)
   
     B. Chromatin
   
          1. Nucleic Acid + Protein
   
     C. Is protein the genetic material?
   
          1. 1920s-1940s
   
                a. Nucleic acid is the genetic material
   
     D. Nucleic Acid
   
          1. DNA (deoxyribonucleic acid)
   
          2. RNA (ribonucleic acid)
   
III. Chemical Composition of Nucleic Acids
   
     A. 1940s
   
          1. Nucleic acids are composed of nucleotides:
   
               a. Phosphate Group
   

   
               b. Sugar (a pentose)
   
                    i. Ribose
   

   
                    ii. Deoxyribose
   

   
               c. Nitrogen Bases
   
IV. Nitrogen Bases
   
     A. Purines
   
          1. Adenine  (DNA and RNA)
   

   
          2. Guanine  (DNA and RNA)
   

   
     B. Pyrimidines
   
          1. Cytosine (DNA and RNA)
   

   
          2. Thymine (DNA only)
   

   
          3. Uracil (RNA only)
   

   
V. Structure of DNA
   
     A. 1953
   
          1. James Watson (b. 1928) and
               Francis Crick (1916-2004) 
   
               a. DNA is composed of two chains of
                    nucleotides
   
               b. Adenine and Thymine always pair;
                    Guanine and Cytosine always pair
                    (Complementary Base Pairing)
   
               c. The two chains of nucleotides are
                    formed into a double helix
   
   
   
VI. Structure of RNA
   
     A. RNA and DNA Compared
   
           1. RNA is similar to DNA, but it is usually
               single stranded (only one chain of
               nucleotides)
   
           2. In RNA ribose is used in place of
               deoxyribose
   
           3. In RNA uracil is used in place of thymine
   

   
VII. Double Helix Structure Explains 3 Things:
   
     A. Replication (Duplication) of DNA
   
          1. The double helix of DNA unwinds and
               the two strands separate
   
          2. Each old DNA strand is used as a
               template to build a new strand of DNA
               (using complementary base pairing)
   
          3. The result is two new DNA molecules,
               each of which is identical to the original
               DNA molecule
   
     B. Production of RNA
   
          1. The double helix of DNA unwinds and
               the two strands separate
   
          2. One DNA strand is used as a template
               to produce a strand of RNA (using
               complementary base pairing)
   
     C. Storage of Genetic Information
   
          1. The sequence of nitrogen bases encodes
               the genetic information
   
VIII. Chromatin and Chromosomes
   
     A. Chromatin
   
          1. Nucleic Acid (DNA)
   
          2. Proteins (Histones)
   
               [String Demonstration]
   
     B. Chromosomes
   
          1. Nucleosomes (DNA & histones)
   
          2. Chromatids
   
          3. Chromosomes
   
IX. Summary

Page obtained from link at URL: http://www.ric.edu/faculty/jmontvilo/109.htm Prepared by Jerome A. Montvilo, Ph.D. for the use of his students. Copyright © by Jerome A. Montvilo. All rights reserved. Please send questions, comments, or suggestions to jmontvilo@ric.edu. Last updated 15 January, 2008