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What do genes do?

George Beadle and Edward Tatum. “One ought to be able to discover what genes do by making them defective”. What do genes do?. What do genes do?. Their Model Organism:. Neurospora crassa. One Gene–One Enzyme Hypothesis. Neurospora crassa. One Gene–One Enzyme Hypothesis.

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What do genes do?

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  1. George Beadle and Edward Tatum “One ought to be able to discover what genes do by making them defective” What do genes do?

  2. What do genes do?

  3. Their Model Organism: Neurospora crassa

  4. One Gene–One Enzyme Hypothesis Neurospora crassa

  5. One Gene–One Enzyme Hypothesis Adrian Srb and Norman Horowitz (1944)

  6. One Gene–One Enzyme  One Gene–One Protein  One Gene–One Polypeptide

  7. A Problem:

  8. The Central Dogma of Biology:

  9. 3’ G C G T T G G A C 5’ 3’ A C G T T G G A C 5’ DNA 5’ U G C A A C C U G 3’ mDNA 5’ C G C A A C C U G 3’ Leu Asn Cys Asn Leu Arg proteins

  10. The Central Dogma of Biology:

  11. Exceptions to the Central Dogma: 1. 2.

  12. Cracking the Genetic Code = 20 amino acids? George Gamow’s Hypothesis

  13. Cracking the Genetic Code Analyzed the reading frame by making additions / deletions: Normal: “The fat cat ate the rat” 1 deletion: “The atcatatet her at” 2 deletions: “The tca tat eth era t” 3 deletions: “fat cat ate the rat” Francis Crick and Sydney Brennar

  14. Triplet Code! • Redundant • Unambiguous • Nearly universal • Conservative

  15. Some Quick Decoding Practice… Who Murdered T.M.R.? Use decoder on page _____ in textbook!

  16. When the code goes awry.. • Mutation =

  17. Point Mutation Classification • In terms of fitness… • Beneficial • Neutral • Deleterious • In terms of the code… • Silent • Missence (replacement) • Nonsense • Frameshift

  18. Chromosome Mutation Classification • Deletion = • Addition / Duplication = • Inversion = • Translocation =

  19. Chromosome Mutation Classification

  20. Protein Synthesis: 2 Stages Stage 1: Stage 2:

  21. Every group member should contribute equally (indicate where) • Every term should have an entry / explanation • Include images / links to videos whenever possible / helpful • You are not expected to cite sources. • Share the completed document with Ms. Hines by Wednesday at midnight at the latest (hopefully you can finish today!) From Gene to Protein:Outlining Protein Synthesis

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