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Protein Synthesis

Protein Synthesis. From DNA to protein And viruses And bacteria. 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). Beadle and Tatum. REMEMBER US?.

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Protein Synthesis

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

  2. 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)

  3. Beadle and Tatum REMEMBER US?

  4. George Beadle and Edward Tatum during the late 1930s and early 1940s • Using Neurospora crassa bread mold determined "one gene one enzyme hypothesis"

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

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

  7. Three Bases Lingo • DNA Triplet ATC • mRNA Codon UAG tRNA Anti-codon AUC

  8. 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 • rRNA–ribosomal RNA – plus protein makes up a ribosome

  9. Transcription: DNA to mRNA • DNA never leaves the nucleus • It codes to mRNA to take the message outside the nucleus • TRANSCRIPTION YOUTUBE (1:53)

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

  11. 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)

  12. SPLICING RNA Or Primary RNA Mature mRNA

  13. SPLICING ANIMATIONsnRNP’s Spliceosome Seriously detailed splicing youtube (1:39) McGraw-Hill How Splicesosomes Process RNA • Before the mRNA leaves the nucleus, the introns are removed, and the exons are spliced together.

  14. Exons leave the nucleus Mature mRNA leaves

  15. Transcription Initiation Control

  16. 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

  17. Transcription Terminator • mRNA is cut free from DNA

  18. 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)

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

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

  21. tRNA • transports amino acids to ribosomes • There is a specific amino acid for each tRNA

  22. Job of tRNA • Complements the codon of mRNA and picks up the appropriate amino acid ANIMATION: Animation of Translation

  23. 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)

  24. A P E Sites at the RibosomeTranslocation: movement of tRNA across the ribosome

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

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

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

  28. Translation Elongation tRNA brings amino acids to the ribosome

  29. Translation Termination mRNA reaches one of the STOP codons • Bond breaks the last tRNA and its amino acid to release the polypeptide bond

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

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

  32. Answer • Methionine

  33. 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?

  34. 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…

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

  36. Mutagens

  37. 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

  38. Gene (point)mutations SUBSTITUTION – Replace one base for another. Minimal effect ADDITION – Adding a base DELETION – removing a base Addition/deletions cause a complete Frame Shift that affects the whole gene.

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

  40. More Mutation Lingo • Nonsense mutation = change an amino acid into a STOP codon • Missence mutation = change the amino acid coding • Silent mutation = no change in protein product

  41. Translocation Inversion Segment of a same chromosome is turned end to end Chromosome Mutations has moved one segment of a chromosome to a different chromosome

  42. Translocation

  43. Translocation 9 and 22

  44. Cystic Fibrosis Deletion

  45. ALBINISM Albinism is due to a mutation of the melanin pigment gene. A one base substitution results in only 1 amino acid being in error.

  46. AAGGTTCGGAGT (DNA) type of mutation Amino acids AACGTTCGGAGT:____________________ AAGGTCTCGGAGT:____________________ AAGGTTCGAGT:_______________________

  47. ANSWER- • Substitution (C for the G) • Insertion (the C) • Deletion (the G)

  48. Chromosomal mutations Affect the entire chromosome - often fatal. Mutagens can cut up DNA into pieces. When Repair mechanism reassembles them, they may be in the wrong order.

  49. Oncogenes Genes that when mutated result in cancer. EXAMPLE:BRCA1 and BRCA2Found to cause breast cancer on 81-kb region of human chromosome 17

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