Protein Synthesis

1. Protein Synthesis From DNA to protein And viruses And bacteria

2. CENTRAL DOGMA: From DNA to Protein • OVERVIEW FIRST Central Dogma Youtube (3:01) • DNA wrapping, transcription, translation Youtube (7:46)

3. Central Dogma • You Tube Protein Synthesis (2:51) • DNA Transcription and Protein Assembly (3:02) From DNA to proteins • FROM GENOTYPE TO PHENOTYPE (From DNA to proteins)

4. First Proposed by • Francis Crick (1958) • Later : Nirenberg said, "DNA makes RNA makes protein."

5. Beadle and Tatum REMEMBER US? • Using Neurospora crassa bread mold determined "one gene - one enzyme hypothesis"

6. Protein Synthesis Overviewget “Central Dogma” and “Protein Synthesis” Worksheets • DNA Replication, Transcription, Translation Youtube (8 mins)

7. Learn these Terms • Transcription = DNA → mRNA • Translation = mRNA → protein

8. Three Bases Lingo • DNATriplet ATC • mRNA Codon UAG tRNA Anti-codon AUC

9. The 3 RNA’s • mRNA – messenger RNA – codes from DNA in the nucleus to take the genetic code to the ribosome in the cytoplasm • tRNA– transfer RNA – brings a specific amino acid to the ribosome + cytoplasm • rRNA–ribosomal RNA – plus protein makes up a ribosome

10. ANIMATIONS • McGraw-Hill Transcription Animation • McGraw-Hill Translation Animation

11. Transcription: DNA to mRNAMcGraw Hill Transcription Animation • DNA never leaves the nucleus • It codes to mRNA to take the message outside the nucleus • TRANSCRIPTION YOUTUBE (1:53) • Transcription (1:27)

12. RNA polymerase(RNAP) • The enzymes that makes RNA from the DNA template DNA RNAP RNA

13. REMEMBER: U replaces T in all RNA’s

14. Not all RNA nucleotides make the cut:Introns and Exons • Primary mRNA = exons + introns • INTRONS = discarded, noncoding region of mRNA • EXONS = the coding regions, spliced together RNA are called also = Mature mRNA • RNA Splicing Youtube (1:38)

15. SPLICING RNA Or Primary RNA Mature mRNA

16. SPLICING ANIMATIONsnRNP’s Spliceosome McGraw-Hill How Splicesosomes Process RNA • Before the mRNA leaves the nucleus, the introns are removed, and the exons are spliced together.

17. Exons leave the nucleus Mature mRNA leaves

18. Transcription Initiation Control

19. Transcription Promotors • DNA sequences at start site (recognize TATA BOX) • RNA polymerase and accessory proteins (transcription factors) bind to the promoter to initiate production of an mRNA transcription. TATA

20. Transcription Terminator • mRNA is cut free from DNA

21. The mRNA travels out of the nucleus through nuclear pores to a ribosome in the cytoplasm • The mRNA binds to a ribosome • Ribosome translates codons (use chart)

22. TRANSLATION • Coding from mRNA to making protein (at the ribosome) • DNA Translation Youtube (2:06)

23. TRANSLATION • mRNA (genetic language) needs to be translated into protein language (chain of amino acids) • Transcription Youtube (2:06)

24. tRNA • transports amino acids to ribosomes • There is a specific amino acid for each tRNA • Anticodon for that amino acid

25. Job of tRNA • Complements the codon of mRNA and picks up the appropriate amino acid tRNA animation (1:29)

26. Note the A P E sitesCentral Dogma youtube(3:03) • A site – Amino acid is dropped off • P site – Polypeptide builds • E site – tRNA exits (after giving its amino acid to building polypeptide chain) APE sites of Ribosome youtube (1:31) McGraw Hill EPA 2:24

27. A P E Sites at the RibosomeTranslocation movement of tRNA across the ribosomeTRANSLATION Virtual Cell Animation (Nice APE sites) (3:32)

28. There are 20 Amino Acids • These 20 are shared by all living organisms • What does CAC code for? • histidine

29. Notice AUG codon means “start” building a new protein. UAA, UAG, UGA mean “stop’ building the protein.

30. Translation Initiation • mRNA attaches to the ribosome (AUG –start codon)

31. Translation Elongation tRNA brings amino acids to the ribosome

32. Translation Terminationvideo 1:01 mRNA reaches one of the STOP codons • Bond breaks the last tRNA and its amino acid to release the polypeptide bond

33. Cooooool Protein Synthesis 3-D • CENTRAL DOGMA (2:52)

34. transcription translation

35. All mRNA’s start with AUG, so all DNA genes start with______?

36. Answer • Methionine • Is always the STARTamino acid

37. GENE REGULATION pp. 210-11 • Remember that question on the DNA Extraction lab: “Do all cells in your body have the same DNA?” • YES • Just not all genes are expressing at the same time.

40. EXAMPLE: Lac operon • E. coli used to produce lactose-using enzymes: • lacZ codes for β-galactosidase • lacY for lactose permease • lacA codes for galactoside O-acetyltransferase

41. Gene Expression • Gene promoter = where RNA polymerase attaches and initiates transcription • Operator = acts like a switch – between promoter and genes • Represser = turns off transcription-binds to operator and blocks RNA polymerase

42. OPERON = • Operator + represser + promoter + genes

44. GENE REGULATIONturning on and off of genes • Lac operon control 2:09 • McGraw Hill Lac Operon

45. THINK: • What would happen if something caused the base sequence to change? • What sorts of things could cause this? • Could the base changes be repaired? • Would those changes be passed on to the individual’s offspring?

46. MUTATION: A change in the base sequence of a gene resulting in a different base sequence and thus different amino acid sequence. What causes mutations? MUTAGENS Thalidomide baby…

47. MUTAGEN • = any source of mutation is a physical or chemical agent • EX: X-rays • UV light • cigarette components • Hazardous chemicals

48. Mutagens

49. Mutation Animations • BBC - Education Scotland - Higher Bitesize Revision - Biology - Genetics and adaptation - Mutations: Revision 2 • EXPLAIN HOW EACH MUTATION IS DIFFERENT FROM THE ORIGINAL DNA SEQUENCE

50. Mutation Lingo • Mutation = any change in nucleotide sequence of DNA • Reading frame = triplet grouping • Mutagenesis = creation of mutations