Translation

• A site


  Recruits tRNA compimentary to the codon in the A site holding the next amino acid to be added to the polypeptide chain
• P site

  holds tRNA carrying the growing polypeptide chain
• E site

  releases deacylated which is ejected from E site
• initiation

  1. the small subunit of the ribosome binds onto the mRNA transcript
  2. the small subunit reads along mRNA transcript until it encounters the start codon , AUG. this then recruits the tRNA molecule with complimentary anti-codon according to base pairing. this holds the amino acid Met.
  3. the large ribosome subunit is recruited and teh tRNA (met)is held in the P-site
• elongation

  refers to the building of the polypeptide chain
• elongation

  1. the next tRNA with the next amino acid and complimentary anti-codon are recruited to the a-site
  2. /3. the amino acid on the tRNA on the p-site binds to the amino acid on the tRNA on the a-site forming a peptide bond. A-site tRNA is not holding the polypeptide chain and the P-site tRNA is not deacylated
• translocation

  refers to the ribosome moving through mRNA by 1 codon
• translocation

  the ribosome complex shifts through the mRNA by 1 codon. the tRNA holding the polypeptide chain in the A-site shifts to the P-site. the deacylated tRNA on the P-site shifts to the E-site and is ejected

  the a-site is now available for the next tRNA recruitment and the process repeats
• termination

  1. this process continues until the ribosome encounters the stop codon. this will recruits a release factor
  2. the release factor breaks bonds from the tRNA an polypeptide chain releasing the polypeptide chain
  3. then disassembles the ribosomal complex ending translation
• Recycling of amino acids

  Lysosome organelles may be required in the recycling of unrequired proteins using hydrolytic enzymes

  Through a cascade of enzyme controlled reactions, ubiquitcan chemically highlight proteins that should be broken/recycled. These ubiquitinated proteins go through a proteasome and break down into peptides for recycling and further translation
• mRNA Digestion

  As mRNA provides instructions required by ribosomes the longevity of transcripts determine expression levels of a gene. mRNA transcripts can be broken down by nucleases to form single nucleotides that can be recycled
• Polymerase chain reaction

  1. High temp hydrolyses H+ bonds creating 2 single strand templates
  2. Temp lowers to facilitate the primer binding
  3. taq pol can now bind. It reads the nitrogenous base sequence of the sst and recruits complimentary nucleotides bases to NBP
  4. the process repeats several times to amplify DNA. it is done by a thermocycler
• Post translational modification of a polypeptide

  Insulin structure