pt 1

DNA -> RNA -> protein

One-gene/one-polypeptide hypothesis (was one-gene/one-enzyme hypothesis)

• Mutations

• Reading frame

  • Frameshift mutation

Transcription (DNA 🡪 mRNA)

• Prokaryotic transcription

  • Promoter

  • Start site / initiation

  • Elongation (5’-to-3’)

  • Termination site

  • Happens at same time as translation

• Eukaryotic transcription

  • More complex (more enzymes)

  • Initiation

  • Elongation 

  • Termination 

  • Posttranscriptional modifications to mRNA

    • 5’ cap

    • 3’ poly-A tail

    • Splicing

      • Introns vs. exons

      • Alternative splicing 

Translation (mRNA 🡪 protein)

• Uses tRNA + ribosomes (rRNA) to read the mRNA strand

• tRNA has anticodon (complementary to mRNA codons)

• Ribosome has multiple tRNA binding sites (A, P, E)

• Initiation, elongation, termination

  • Start codon (AUG)

  • Stop codon (UUA, UGA, UAG)

Mutations

• Point mutations

• Base substitutions

  • Silent mutation

  • Missense mutation

  • Nonsense mutation

• Frameshift mutations