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February 10, 2012

February 10, 2012. Agenda. Objectives. I will know the 4 bases and how they pair up I will know the basic structure of the sugar-phosphate backbone. Opening Bellwork Discussion of DNA Video Clip Get out a blank sheet of paper Structure of DNA Lecture and Discussion Review Exams.

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February 10, 2012

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  1. February 10, 2012 Agenda Objectives I will know the 4 bases and how they pair up I will know the basic structure of the sugar-phosphate backbone. • Opening Bellwork • Discussion of DNA • Video Clip • Get out a blank sheet of paper • Structure of DNA • Lecture and Discussion • Review Exams

  2. CHAPTER 12: DNA and RNA

  3. Building block of DNA • _____________ are the building block • Consist of: • 5-Carbon sugar (Deoxyribose), • Phosphate group, and • Nitrogenous base: • Adenine and Guanine : _____________ • Thymine and Cytosine: _____________ • Sugar and Phosphate groups form __________ while nitrogenous bases ______________ in between. Nucleotides Purines (2 Rings) Pyrimidines (Only one ring) backbone hydrogen bond

  4. Figure 12–5 DNA Nucleotides Section 12-1 Purines Pyrimidines Adenine Guanine Cytosine Thymine Phosphate group Deoxyribose

  5. Figure 12–7 Structure of DNA Section 12-1 Nucleotide Hydrogen bonds Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

  6. The Structure of DNA = Phosphate = Deoxyribose (5-c sugar) = N-base (A-T) (G-C) Hydrogen bonds

  7. February 14, 2012 <3 Agenda Objectives I will be able to summarize each of the following peoples experiments and know why they were significant to our understanding of DNA: Griffiths Avery Hershey and Chase Franklin and Wilkins Watson and Crick • Opening Bell Work • Diagram DNA Structure • Lecture and Discussion • Experiments that gave us DNA • Closing Bell Work • Most interesting experiment • Homework: • 12.1 Outline – 2 Pages

  8. Griffith and Transformation • Griffith was trying to figure out how bacteria made people sick. • Specifically, Pneumonia • 2 Pneumonia strains isolated from mice. • Smooth • Did make people sick. • Rough • Did NOT make people sick

  9. Rough and smooth Bacteria

  10. Griffiths • Injected mice with • disease causing strain – died - X( • Non-disease causing strain - lived • Thought it might be poison caused by bacteria. • Took disease causing bacteria, heated them to kill the bacteria, then injected it into mice. • Lived

  11. Griffiths Transformation • Mixed heat killed, disease causing bacteria with live harmless ones • Injected it into mice • Neither should make mice sick, but what was the result? • Mice got pneumonia and died • Dead, harmful bacteria had passed along ability to make mice sick to the harmless bacteria • Known as TRANSFORMATION  one strain of bacteria has been changed into another. DNA had been transferred.

  12. Figure 12–2 Griffith’s Experiment Section 12-1 Heat-killed, disease-causing bacteria (smooth colonies) Harmless bacteria (rough colonies) Harmless bacteria (rough colonies) Control(no growth) Heat-killed, disease-causing bacteria (smooth colonies) Disease-causing bacteria (smooth colonies) Dies of pneumonia Dies of pneumonia Lives Lives Live, disease-causingbacteria (smooth colonies) Transforming factor altered the Rough (harmless) Bacteria into Smooth (harmful) Bacteria

  13. Avery, MacLeod and others • Did the same experiment as Griffith • except with isolating the biological compounds • Carbohydrates, Lipids, Proteins and DNA • See what was necessary for transformation • Only DNA was necessary for the transformation to occur; therefore it is the transforming factor. • Discovered DNA stores and transmits the genetic information from one generation to the next.

  14. Hershey-Chase Experiments • Alfred Hershey and Martha Chase (a girl!) studied viruses • A virus is a non living particle, smaller than a cell, that can infect people. • Bacteriophages are a type of virus that can infect bacteria. • Made of DNA or RNA and a protein

  15. Bacteriophages • When a bacteriophage enters a bacteria, it injects genetic material. • Typically the genetic material is coding to make more bacteriophages. • When the bacteria gets too full of bacteriophages, it splits open and dies. • releasing TONS more bacteriophages

  16. Hershey-Chase Experiments • Hershey and Chase wanted to determine what part of the virus was the infecting agent • Protein coat or DNA/RNA • Grew virus’ on a plate with radioactive isotopes. • Phosphorus – To Tag the DNA (proteins don’t have P) • Sulfur – To tag the protein (DNA doesn’t have S) • If they found radioactive P or S in the bacteria cells, they would know what had been injected by the virus.

  17. Hershey- Chase – RESULTS! • Only found radioactive Phosphorus in the bacteria. • What does that mean? • The genetic material of the virus was DNA, not protein!

  18. Hershey Chase Experiment

  19. Figure 12–4 Hershey-Chase Experiment Section 12-1 Bacteriophage with phosphorus-32 in DNA Phage infectsbacterium Radioactivity inside bacterium Bacteriophage with sulfur-35 in protein coat Phage infectsbacterium No radioactivity inside bacterium Validated that DNA is the agent of genes

  20. Chargaff • Noticed the % of Guanine and Cytosine were roughly equal • Noticed the % of Adenine and Thymine were roughly equal • No idea why, however

  21. Percentage of Bases in Four Organisms Source of DNA A T G C Streptococcus 29.8 31.6 20.5 18.0 Yeast 31.3 32.9 18.7 17.1 Herring 27.8 27.5 22.2 22.6 Human 30.9 29.4 19.9 19.8

  22. Rosalind Franklin and Maurice Wilkins • X-Ray Diffraction • Beams of high powered X rays at concentrated samples of DNA to try and see structure. • Received very little credit and died of cancer

  23. Watson and Crick • Watson and Crick were together trying to figure out the structure • By making cardboard and wire structures. • Using Franklins X-Ray pictures, they were able to determine • DNA is a double helix (2 strands wound around each other) • Base pairing explained Chargaffs Rules

  24. Evidence of DNA Structure • X-Ray Diffraction • Rosalind Franklin and Maurice Wilkins • Chargaff base pairing • A- • G- • Watson and Crick Final DNA model • Double • Nobel Prize winners in 1962 T C Helix

  25. February 14, 2012 Agenda Objectives I will be able to summarize each of the following peoples experiments and know why they were significant to our understanding of DNA: Griffiths Avery Hershey and Chase Franklin and Wilkins Watson and Crick • Opening Bell Work • Diagram DNA Structure • Lecture and Discussion • Experiments that gave us DNA • Closing Bell Work • Most interesting experiment • Homework: • 12.1 Outline – 2 Pages

  26. February 15, 2012 Agenda Objectives I will be able to summarize and diagram the process of DNA replication know how and when it takes place what enzyme it uses to aid in the replication process • Opening Bell Work • Summarize each of the experiments from yesterday • Lecture and Discussion • 12.2 – DNA Replication • DNA Replication Drawing • Video Clip • Closing Bell Work • Write a Paragraph describing the DNA replication Process • Homework • 12.2 Outline (2 Pages)

  27. 12-2: Chromosomes and DNA Replication lack nuclei • DNA and Chromosomes a. Prokaryotes ___________and their DNA is found in the cytoplasm. b. It consists of a _____________________ DNA molecule c. This is the cells ______________ d. Eukaryotic DNA is more complicated e. It is not free in the cytoplasm but is contained in the _________ of the cell. f. It forms a _______ of chromosomes not just one g. humans have __, Drosophila have __ and a Sequoia tree have __. large, singular circular chromosome nucleus number 8 46 22

  28. 1. DNA Length a. ______ molecules are surprisingly long b. prokaryotes DNA of E. coli is over __ million base pairs long. c. it must be ___________________ that is one-one thousandths it’s size. (see fig. 12-9) d. How does it do this? DNA 4 packed into a space

  29. eukaryotic cells 2. Chromosome Structure a. DNA in _________________ is even more tightly packed. b. Eukaryotic DNA has over __________ DNA base pairs and is measured at over 1 meter of DNA c. It is folded into a tiny _____________ d. How does it do this? e. Eukaryotic DNA contains both DNA and ___________(proteins) packed together to form ____________. 6 billion chromosome histones chromatin

  30. DNA beadlike nucleosome 2. Chromosome Structure (cont.) f. Chromatin consists of ______ tightly wrapped around histones to form a _________ structure called a ___________. g. Nucleosomes pack with one another to form a thick fiber and are ____________ by a system of ________________. h. During the _________ these fibers are dispersed and __________. i. During _________ they are condensed and coiled into the ________ chromosomes. j. What do nucleosomes do? _____________ _______________________________________ _______ shortened loops and coils cell cycle not visible mitosis visible they are able to fold the DNA into the tiny space of the cell nucleus

  31. Nucleosome Chromosome DNA double helix Coils Supercoils Histones DNA Supercoiling into Chromosomes

  32. Genetic code • DNA Replication Remember what Watson and Crick learned about DNA: - Holds the in the sequence of nucleotides • DNA Is - consists of two parallel strands of sugar-phosphate groups. Pairs of nitrogenous bases link the two strands together, forming a • The Nitrogen (N)-base pairing is because each strand can be used to make the other strand. double stranded double helix complementary

  33. prokaryotes continues in two directions • DNA Replication • In ____________ replication begins on one point on the chromosome and ___________ ______________ • In ____________ the DNA replication occurs in ___________ of places and occurs in ____ _____________ until each chromosome is copied. • The sites where separation and replication occur are called _______________. eukaryotes both directions hundreds replication forks

  34. The Replication of DNA Try your own: A A T T T C G A T G G C (Strand 1) (Strand 2) A. This aids in DNA replication. T T A A A G C T A C C G Each strand of the double helix serves as a template, or model, for the new strand

  35. The Replication of DNA When a cell divides to form new cells, the DNA must REPLICATE to ensure new cells have a new copy. B. Q: Why does DNA need to replicate? A: C. DNA replication (aka: DNA synthesis) is done with the aid of . Enzymes (DNA Polymerase)

  36. The Replication of DNA Separate or “unzip” the two strands of the double helix. D. The Enzymes: 2. 3. 4. Insert the appropriate bases. Covalently bond the sugar to the phosphate Proofread the bases to make sure they were paired correctly

  37. Original strand DNA polymerase New strand Growth DNA polymerase Growth Replication fork Replication fork Nitrogenous bases New strand Original strand DNA Replication

  38. The Replication of DNA (Summary) The Hydrogen Bonds (between N-bases) break and “unzips” the DNA • The steps in DNA replication 1. 2. Each strand serves as a template for the attachment of complementary bases

  39. The Replication of DNA Base Pairing 2 New Strands Unzip

  40. February 15, 2012 Agenda Objectives I will be able to summarize and diagram the process of DNA replication know how and when it takes place what enzyme it uses to aid in the replication process • Opening Bell Work • Summarize each of the experiments from yesterday • Lecture and Discussion • 12.2 – DNA Replication • DNA Replication Drawing • Video Clip • Closing Bell Work • Write a Paragraph describing the DNA replication Process • Homework • 12.2 Outline (2 Pages)

  41. February 16, 2012 Agenda Objectives I will know The difference between the types of RNA The definition of transcription and be able to summarize the process Be able to diagram what transcription would look like. • Opening Bell Work • Diagram DNA replication • Lecture and Discussion • 12.3a – RNA, Transcription • Drawing • Video Clip • Closing Bell Work • Summarize Transcription Process • Homework • 12.3a (Pgs. 300-303) Outline • ¾ Page

  42. 12-3 RNA and Protein Synthesis proteins Proteins are made outside the nucleus on ribosomes • DNA holds the genetic code to make • DNA • How does DNA get the code outside the nucleus? A: Cannot leave the nucleus RNA(Ribonucleic Acid) acts as a messenger between DNA and the ribosomes and carries out the process by which proteins are made from Amino Acids. DNA mRNA Protein

  43. Protein Synthesis overview

  44. mRNA and DNA interaction Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only) RNApolymerase DNA RNA

  45. I. The Structure of RNA A. Similar to DNA with a few differences: Single Stranded (can form double strand if it folds back on itself). Double Stranded Deoxyribose Ribose A-U G-C A-T G-C

  46. The Structure of RNA B. 3 types of RNA: • mRNA (messenger RNA) 2. tRNA (transfer RNA) • rRNA (ribosomal RNA) Copies the code off DNA in the nucleus and brings it out of the nucleusto the ribosomes Carries amino acids to the ribosomes Along with proteins, rRNA makes the subunits of the ribosomes

  47. Different Forms of RNA 50S 30S

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