1. Protein Synthesis

3. DNA mRNA

4. DNA Cannot the nucleus Sends to the cytoplasm via Its base sequence (called a codon) determines the amino acid in proteins DNA and acts as a template for synthesis of mRNA (RNA)

5. mRNA Base sequence is to DNA 3 base sequences (called ), which are to the triplet codons in DNA determines the amino acid sequence in proteins Travels from the to the Process through which is formed from is called

6. Transcription Initiation: RNA polymerase the DNA to find a region Once it finds the region, the polymerase will the DNA and will begin to at a slow rate (about 10 nucleotides)

7. Transcription Elongation Once the promotor region is (transcribed) the RNA polymerase will begin a highly processive transcription process in the ’ to ’ direction (approx. bases/second) The base pairing is as follows: –Adenine in RNA will pair –Cytosine in RNA will pair –Uracil in RNA will pair –Guanine in RNA will

8. Transcription Termination A rich region at the end of the gene causes hydrogen bonds and so the RNA polymerase complex off, terminating translation

9. mRNAamino acids translation

10. rRNA Ribosomes are made up of (RNA) and proteins The ribosome has a structural purpose in protein synthesis, where it hosts translations mRNA codons are read and specific tRNA’s are signalled

11. tRNA tRNA = RNA Is made up of Found the in the cytoplasm Attaches to in the cytoplasm and the amino acid to ribosome Each tRNA has a 3 base sequence called the and this sequence mRNA at the ribosome

12. Translation Initiation –mRNA finds the ribosome and forms a –The first moves into place as the on the find and attach to the codons on the mRNA in the ribsosome –The first codon always reads – known as the codon

13. Translation Elongation –As mRNA shifts along (by ), new molecules bring in amino acids to the –The amino acids on the join (via peptide bond) to form a chain

14. Translation - elongation

15. Translation Termination –Eventually, the ribosome will read a codon on the mRNA –The stop codon does not code for any, and so the chain will be released from the –The is also released and returned to the nucleus to be broken down into nucleotides, if needed

16. Protein Synthesis Protein synthesis is now. The polypeptide chain is to act as a protein or be combined with other polypeptide chains to form a.

17. Proteins: 4 levels of organization The amino acid sequence determines the three-dimensional structure of a protein The structure of a protein determines the proteins function 4:3

18. Summary

19. Determine the AA sequence

20. By the end of this section you should be able to: Identify the roles of DNA, messenger RNA (mRNA), transfer RNA (tRNA), and ribosomes in the processes of transcription and translation, (including initiation, elongation, and termination) of Protein synthesis Determine the sequence of amino acids coded for by a specific DNA sequence (genetic code), given a table of mRNA codons Identify the complementary nature of the mRNA codon and the tRNA anti-codon