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Lesson Overview

Lesson Overview. 12.1 Identifying the Substance of Genes. Griffith ’ s Experiments. Griffith isolated different strains of bacteria. Only one caused pneumonia. Griffith ’ s Experiments. When injecting mice with bacteria , the mice .

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Lesson Overview

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  1. Lesson Overview 12.1 Identifying the Substance of Genes

  2. Griffith’s Experiments • Griffith isolated different strains of bacteria. • Only one caused pneumonia.

  3. Griffith’s Experiments • When injecting mice with bacteria, the mice . • When injecting mice with bacteria, the mice stayed .

  4. Griffith’s Experiments • First, Griffith took the , them, and then injected the them into mice. • Mice , showing that it wasn’t a toxin the bacteria produce.

  5. Griffith’s Experiments In Griffith’s next experiment, he mixed the S-strain with R strain and injected the mixture into mice.  The mice .

  6. Transformation • Process called - one type of bacteria is changed into another. • Because transformed bacteria inherited ability to cause disease, Griffith concluded the transforming factor was a .

  7. The Molecular Cause of Transformation • Avery proteins, lipids, carbohydrates, and RNA. • Transformation still .

  8. The Molecular Cause of Transformation • Then destroyed and transformation did occur. • Therefore, DNA was the transforming factor. • Meant that DNA stores and transmits genetic .

  9. Bacteriophages • - virus that infects bacteria

  10. The Hershey-Chase Experiment Hershey and Chase studied a bacteriophage with a DNA core and a protein coat. Wanted to determine if the protein or DNA changed bacteria Hershey and Chase grew viruses containing P-32 and S-35

  11. The Hershey-Chase Experiment • Bacteria contained P-32 , found in . • Hershey and Chase confirmed Avery’s results - that was the genetic material found in .

  12. The Role of DNA • DNA can , copy, and genetic information

  13. Lesson Overview 12.2 The Structure of DNA

  14. Nucleic Acids and Nucleotides • Located in . • Made up of . • Three components: a 5-carbon sugar called , a group, and a base.

  15. Nucleic Acids and Nucleotides • DNA has four nitrogenous bases: adenine, guanine, cytosine, and thymine, or .

  16. Chargaff’s Rules • Chargaff discovered the amount of [A] and [T] bases are almost . The same is true for guanine [G] and cytosine [C]. • - and is known as “Chargaff’s rules.”

  17. Franklin’s X-Rays • Rosalind Franklin used X-ray diffraction that showed: • DNA has twisted around each other. • The nitrogen bases are near the .

  18. The Work of Watson and Crick • Franklin’s X-ray pattern enabled Watson and Crick to build a model of DNA. • Built 3-D model of DNA in a .

  19. Antiparallel Strands • DNA strands are “antiparallel”— they run in directions. • Lets nitrogenous bases join at center and allows each strand to carry nucleotides.

  20. Hydrogen Bonding • bonds form between bases and hold strands together. • Hydrogen bonds are weak and allow strands to .

  21. Base Pairing • Fit between A–T and G–C nucleotides called .

  22. 12-3 DNA Replication Federoff

  23. Eukaryotic DNA Replication • Step 1 – unzips the DNA molecule.

  24. Step 2 – DNA adds on complementary nucleotides.

  25. Step 3 – The strand replicates in instead of continually like the strand. Leading Strand Lagging Strand

  26. Okazaki Fragments

  27. Step 4 –Enzyme joins the fragments on lagging strand.

  28. Step 5 – As replication continues, the strands into helix.

  29. _ • Are the tips of chromosomes make sure genes aren’t lost during replication.

  30. Prokaryotic DNA Replication • Starts at point, and goes in 2 directions until the chromosome is copied.

  31. Prokaryotic vs. Eukaryotic • DNA Replication Process [3D Animation] – Biology / Medicine Animations HD • https://www.youtube.com/watch?v=27TxKoFU2Nw

  32. Lesson Overview 13.1 RNA

  33. The Role of RNA • First step - copy . • RNA, like DNA, is a nucleic acid made of nucleotides. • RNA uses the base sequence copied from DNA to make .

  34. Comparing RNA and DNA • Each nucleotide in both DNA and RNA is made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base. • Three differences between RNA and DNA: • (1) Sugar in RNA is . • (2) RNA is -stranded. • (3) RNA contains instead of thymine (T).

  35. Comparing RNA and DNA • The cell uses DNA “master plan” to prepare RNA “blueprints.” • DNA stays in , while RNA goes to .

  36. Functions of RNA • RNA is like a disposable copy of a segment of DNA, a working copy of a single gene. • RNA assembesinto .

  37. Functions of RNA • Three main types of RNA: • RNA, RNA, and RNA.

  38. Messenger RNA • The RNA molecules that _ instructions are known as messenger RNA ()

  39. Ribosomal RNA • Ribosomal RNA () make up .

  40. Transfer RNA • Transfer RNA () transfers to the ribosome

  41. Making RNA - Transcription • – Turning into .

  42. Transcription • In prokaryotes, RNA and protein synthesis occurs in the . • In eukaryotes, RNA is produced in the and moves to the to produce proteins.

  43. Transcription • Requires RNA polymerase, whichDNA strands to assemble complementary strand of .

  44. Promoters • RNA polymerase binds to . • Promoters show RNA polymerase where to making RNA. • Similar signals cause transcription to .

  45. RNA Editing • Parts of RNA are cut out and stay the nucleus are called . • The remaining pieces, known as , are joined together into the final mRNA, which the nucleus.

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