1. 1 PROTEIN SYNTHESIS: Translation

2. 2 Transcription Translation DNA mRNA Ribosome Protein Prokaryotic Cell DNA  RNA  Protein

3. 3 The Genetic Code 1. is redundant -more than one codon can code for the same amino acid 2.is continuous -reads as a series of 3-letter codons without spaces 3.is nearly universal - almost all organisms build proteins with the same code

4. 4 gene expression the transfer of genetic information from DNA to RNA to protein

5. Translation mRNA is exported to the cytoplasm and processed further by other enzymes to remove the “junk” DNA called introns The final mRNA is transported to ribosomes where translation occurs. Ribosomes read the mRNA in multiples of 3 nucleotides called codons For example: 5’ AUGCCCUCAGAG 3’

6. Codon Table

7. Translation Each codon signals the cell to retrieve and add an amino acid to a growing chain of amino acids using transfer RNA (tRNA). energy is used to both make the amino acids and to join them, ~200 ATP per 50 aa sequence!

8. 8 tRNA transfer RNA ssRNA, ~80 nucleotides, that has an anticodon loop and a 3’ region where an amino acid attaches

9. 9

10. 10

11. 11 Steps of Translation 1.Initiation small ribosomal subunit attaches at 5’cap and scans down the anticodon of tRNA attaches to the AUG start codon of mRNA, using the small ribosomal subunit as “support” –this sets the reading frame

12. 12

13. 13 large ribosomal subunit joins –P (peptide) site: where first tRNA binds –A (amino acid) site: where next tRNA will bind –E (exit) site: where tRNA will leave from the ribosome is made or rRNA and proteins made inside the cell’s nucleus

14. 14 2.Elongation -the large ribosomal subunit catalyzes the peptide bond between the P site and the A site amino acids -mRNA moves forward by one codon

15. 15

16. 16

17. 17

18. 18 3.Termination stop codon is reached, ribosome falls off

19. 19

20. 20 Transcription Translatio n

21. AA sequence = Protein! Once the entire mRNA sequence is read and translated into amino acids the chain of AA’s is released This chain of AA’s folds and contorts into a structure called its tertiary structure*  Finally a functional protein!

22. 22

23. 23 The end….ignore the rest

24. 24 Ribosomes P Site A Site Large subunit Small subunitmRNA AUGCUACUUCG

25. 25 mRNA Codons Join the Ribosome P Site A Site Large subunit Small subunitmRNA AUGCUACUUCG

26. 26 Initiation mRNA AUGCUACUUCG 2-tRNA G aa2 AU A 1-tRNA UAC aa1 anticodon hydrogen bonds codon

27. 27 mRNA AUGCUACUUCG 1-tRNA2-tRNA UACG aa1 aa2 AU A anticodon hydrogen bonds codon peptide bond 3-tRNA GAA aa3 Elongation

28. 28 mRNA AUGCUACUUCG 1-tRNA 2-tRNA UAC G aa1 aa2 AU A peptide bond 3-tRNA GAA aa3 Ribosomes move over one codon (leaves)

29. 29 mRNA AUGCUACUUCG 2-tRNA G aa1 aa2 AU A peptide bonds 3-tRNA GAA aa3 4-tRNA GCU aa4 ACU

30. 30 mRNA AUGCUACUUCG 2-tRNA G aa1 aa2 AU A peptide bonds 3-tRNA GAA aa3 4-tRNA GCU aa4 ACU (leaves) Ribosomes move over one codon

31. 31 mRNA GCUACUUCG aa1 aa2 A peptide bonds 3-tRNA GAA aa3 4-tRNA GCU aa4 ACU UGA 5-tRNA aa5

32. 32 mRNA GCUACUUCG aa1 aa2 A peptide bonds 3-tRNA GAA aa3 4-tRNA GCU aa4 ACU UGA 5-tRNA aa5 Ribosomes move over one codon

33. 33 mRNA ACAUGU aa1 aa2 U primarystructure of a protein aa3 200-tRNA aa4 UAG aa5 CU aa200 aa199 terminator or stop or stop codon codon Termination

34. 34 End Product –The Protein! The end products of protein synthesis is a primary structure of a proteinThe end products of protein synthesis is a primary structure of a protein A sequence of amino acid bonded together by peptide bondsA sequence of amino acid bonded together by peptide bonds aa1 aa2 aa3 aa4 aa5 aa200 aa199

35. More about different types of DNA you should know about: Centromeric DNA (CEN)Center of chromosome, specialized sequences function with the microtubles and spindle apparatus during mitosis/meiosis. Telomeric DNAAt extreme ends of the chromosome, maintain stability, and consist of tandem repeats. Play a role in DNA replication and stability of DNA. Unique-sequence DNAOften referred to as single-copy and usually code for genes. Repetitive-sequence DNAMay be interspersed or clustered and vary in size. SINEsshort interspersed repeated sequences (100-500 bp) LINEslong interspersed repeated sequences (>5,000 bp) Microsatellites short tandem repeats (e.g., TTA|TTA|TTA)