Lecture on DNA and RNA

Introduction

• DNA as a Molecule
  • Mesmerizing structure
  • Double helix formation
  • DNA's complexity and importance
  • DNA's length comparison with astronomical distances

DNA Overview

• Function
  • Stores genetic instructions
  • 6-billion letter code for living organisms
• Structure
  • 46 chromosomes in somatic cells
  • Nucleic acid family, alongside RNA

Nucleic Acids

• Biological Molecules
  • Include carbohydrates, lipids, proteins, and nucleic acids
  • Nucleic acids are polymers made of nucleotides
• Nucleotide Composition
  • Five-carbon sugar molecule
  • Phosphate group
  • Four nitrogen bases: adenine (A), thymine (T), cytosine (C), guanine (G)

DNA Structure

• Double Helix
  • Pair of polynucleotide molecules
  • Sugar-phosphate backbone
  • Base pairs: A-T and G-C
  • DNA's directionality: 5' to 3' and 3' to 5'
• Base Sequence
  • Determines genetic coding
  • Human chromosome 1 contains 247 million base pairs

DNA Replication

• Process
  • Helicase enzyme unwinds the double helix
  • Leading strand vs. lagging strand
  • DNA polymerase and RNA primase roles
  • Okazaki fragments
  • DNA ligase joins fragments
  • Error checking and correction by DNA polymerase

RNA vs. DNA

• Differences
  • RNA is single-stranded
  • Sugar in RNA is ribose
  • RNA contains uracil instead of thymine

Historical Context

• Discovery of DNA
  • Friedrich Miescher discovered DNA in 1869
  • Rosalind Franklin's contributions with x-ray diffraction
  • Watson and Crick's recognition

Conclusion

• Importance of DNA
  • Celebrated molecule
  • Basis of genetic replication and expression

Each section provides detailed insights into the structure, function, and historical discovery of DNA and its associated processes such as replication and repair, including the differentiation between DNA and RNA.