Protein Synthesis

Confusion Genetics Related Terms

  • genome: total genetic information of an organism
  • gene: stretch of DNA that codes for a protein
  • genetic code: DNA instructions that specifies amino acid sequence of a protein
  • transcription: DNA to RNA, nucleus
  • translation: RNA to protein, ribosome

Regulation of Gene Expression

  • histone modification
  • methylation

Transcription

  • RNA polymerase
    • attaches to promoter region
    • requires assistance of transcription factors
  • helicase
  • template strand vs coding strand
  • mRNA synthesis occurs from 5’ to 3’

mRNA Processing

  • 5’ end: 7 methylguanosine cap
    • guide signal to get it out of nucleus
    • how ribosome recognizes mRNA
  • splicing:
    • removal of introns and rejoinder of exons
  • 3’ end: addition of a polyadenine tail
    • protect enzymes from degradation

Translation

  • Start codon (Met) AUG

  • tRNA

    • clover leaf shaped non-coding RNA
    • acceptor stem: end that combines with an amino acid
    • anticodon loop: contains anticodon

  • rRNA

    • part of ribosomal subunits

  • binding sites

    • mRNA
    • tRNA
    • 3’
    • A site: where tRNA brings new amino acid
    • P site: 1st binding site
    • Exit site
    • 5’

  • RNA is read in 5’ to 3’

Human Genetic Makeup

  • 1 in every 300 base pairs will be a variable region
  • mutations
    • inherited
    • spontaneous: DNA replication
    • induced: exposed to mutagen