Lecture Notes: DNA and RNA Comparison

Introduction

• DNA often gets the spotlight due to its structure and role in genetics.
• RNA is equally important in genetic processes.
• RNA World Hypothesis suggests RNA may have existed before DNA.

DNA vs. RNA

Commonalities

• Both DNA and RNA are nucleic acids, a type of biomolecule.
• Found in all living organisms.
• Composed of nucleotides (monomers): each nucleotide has a phosphate, sugar, and base.

Differences

• Structure:
  • DNA: Double-stranded; strands run antiparallel.
  • RNA: Generally single-stranded.
• Sugar:
  • DNA: Deoxyribose.
  • RNA: Ribose.
• Bases:
  • DNA: Adenine (A), Thymine (T), Guanine (G), Cytosine (C).
    • Mnemonic: Apples in the tree (A with T), Car in the garage (C with G).
  • RNA: Adenine (A), Uracil (U), Guanine (G), Cytosine (C).
    • Mnemonic: Apples under (A with U), Car in the garage.

RNA Types and Roles

• mRNA (Messenger RNA):
  • Carries genetic message from DNA to ribosomes.
  • Can leave the nucleus to transport the message.
• rRNA (Ribosomal RNA):
  • Major component of ribosomes.
• tRNA (Transfer RNA):
  • Transfers amino acids to ribosome, matching mRNA codons.
  • Codon charts show which amino acid corresponds to each mRNA codon.

Protein Synthesis

• DNA codes for traits with the help of RNA.
• Polypeptide chains formed by joining amino acids.
• Proteins composed of one or more polypeptide chains.

Quiz Questions

1. DNA Bases and Base Pairs:
   • 8 DNA nucleotides contain 8 bases, forming 4 base pairs.
2. Complementary DNA Strand:
   • Given bases: A, T, T, G, A, C; Complementary: T, A, A, C, T, G.
3. Complementary RNA Strand:
   • Original DNA: A, T, T, G, A, C; Complementary RNA: U, A, A, C, U, G.

Additional Information

• 3D structures, base turn numbers, chirality not shown in models.
• Further reading recommended for detailed exploration.

Reminder from Amoeba Sisters: Stay curious!