Lecture Notes: DNA vs RNA

Introduction

• DNA often gets credit for its structure.
• RNA is equally important for genetic messaging and protein synthesis.
• RNA World hypothesis: RNA may have come before DNA.

Comparison of DNA and RNA

• Presence in Organisms:

  • Both are found in all living organisms.
  • Eukaryotic cells:
    • DNA is in the nucleus.
    • RNA is found both inside and outside of the nucleus.
  • Prokaryotic cells:
    • No nucleus.

• Type:

  • Both are nucleic acids (biomolecules).

• Monomers:

  • Nucleotides are the building blocks of nucleic acids.
  • Each nucleotide has:
    • Phosphate
    • Sugar
    • Base

• Strands:

  • DNA: Double-stranded (antiparallel).
  • RNA: Generally single-stranded.

• Sugars:

  • DNA: Deoxyribose
  • RNA: Ribose

• Bases:

  • DNA Bases:
    • Adenine (A)
    • Thymine (T)
    • Guanine (G)
    • Cytosine (C)
    • Mnemonic: "Apples in the tree" (A-T) & "Car in the garage" (C-G)
  • RNA Bases:
    • Adenine (A)
    • Uracil (U)
    • Guanine (G)
    • Cytosine (C)
    • Mnemonic: "Apples under" (A-U) & "Car in the garage" (C-G)

Functions of RNA in Protein Synthesis

• Types of RNA:

  • mRNA (Messenger RNA):
    • Carries the genetic message from DNA to ribosomes.
    • Can leave the nucleus.
  • rRNA (Ribosomal RNA):
    • Major component of ribosomes, where protein synthesis occurs.
  • tRNA (Transfer RNA):
    • Transfers amino acids to the ribosome based on mRNA codons.

• Codon Charts:

  • Used to match amino acids with mRNA codons.
  • Amino acids link to form polypeptide chains, which make proteins.

Quiz Questions

1. If I have 8 DNA nucleotides, how many DNA bases and base pairs do I have?
   • 8 bases, 4 base pairs.
2. Complete the complementary DNA bases for A, T, T, G, A, C.
   • T, A, A, C, T, G.
3. Complementary RNA bases for the original DNA segment A, T, T, G, A, C.
   • U, A, A, C, U, G.

Conclusion

• The video introduces basic concepts; further exploration is encouraged.
• Stay curious!