Intro

• Transcription(1)

  ​DNA helicase attaches to the DNA and unwinds double helix

  Hydrogen bonds between the bases are broken

  One strand is used as template

  Complimentary RNA nucleotides join with free DNA bases

  Uracli joins with adenine

  RNA polymerase joins the free nucleotides and forms phosphodiester bonds

  Pre mRNA is formed

  When the RNA polymerase reaches a stop codon the pre mRNA strand is released and the DNA recoils
• Protein Synthesis


  2 strands of DNA molecule seperate

  nucletides join with exposed DNA bases and form mRNA

  The mRNA molecule leaves the nucleus

  A ribosome attaches to the mRNA molecule

  tRNA molecules bring specific amino acids to the mRNA molecule

  Peptide bonds form between the amino acids
• Translation (3)

  1. mRNA leaves the nucleus ​

  2. mRNA attaches to a ribosome​

  3. tRNA (carrying an amino acid) with complimentary anticodon to base pairs with the first codon on the mRNA

  4. The second tRNA attaches to the next codon​

  5. Amino acids joined by a peptide bond. ATP is used​

  6. The ribosome moves along to the mRNA to the next codon.​

  7. The first tRNA detaches and the next tRNA brings the next amino acid.​

  8. A polypeptide chain is made​

  9. Translation stops when a STOP codon is reached.​

  10. The polypeptide chain is released.​
• Splicing (2)

  1. Introns removed
  2. Exons spliced (joined) together to form mRNA molecule
  3. mRNA passes out of nucleus through nuclear pores
  4. mRNA goes to ribosome