Protein Synthesis

Nota:

• mRNA- Messenger Ribonucleic Acid

1. 2. This enzyme breaks up the Hydrogen bonds between the bases, in the DNA.
   1. 3. The DNA separates, leaving its strands exposed.
      1. 4. The RNA Polymerase makes an mRNA using free floating nucleotides
         1. 5. One of the DNA strands is used as a template to make this mRNA.
            1. 6. Complementary base-pairing ensures that the mRNA is an exact match.
               1. 7. Lots of condensation reactions occur to join all the nucleotides.

                  Nota:

                  • The mRNA that is produced is pre-mRNA,  it contains both introns (non-coding bases) and exons.
                  • Splicing occurs to remove the introns.
                  1. 8.Finally, the mRNA detaches and leaves the nucleus.

1. 2. It then attaches to a ribosome in the cytoplasm.
   1. 3. The first set of codon (triplet bases) is translated, on the mRNA.

      Nota:

      • A codon is a set of three bases.
      1. 4. A tRNA with the correct complementary anticodon, comes and pairs up with the first codon.

         Nota:

         • tRNA-Transfer Ribonucleic Acid
         1. 5. The tRNA has an amino acid attached to it at the other end of it.
            1. 6. Next, the second codon on the mRNA is translated using another tRNA.
               1. 7. Now, there are two amino acids next to each other, and they form a peptide bond by a condensation reaction.
                  1. This process is repeated until a stop signal is reached, when the protein detaches and leaves the cell to do its job.