BIOSCI 0851 1st Edition Lecture 5Outline of Last Lecture I. DNAa. Nucleotidesb. MutationsII. Tay-SachsIII. Parts of cellsOutline of Current Lecture II. What is Genetic Material?III. Friedrich MiescherIV. Archibald GarrodV. Hammerlinga. Grafting AlgaeVI. Protein Vs. DNAa. Frederick Griffithb. MacLeod, McCarthy and Avery c. Hershey and ChaseVII. Structure of DNA:a. Phoebus Levine:b. Chargaff: c. Watson and Crick:Current Lecture- At first scientists were unsure whether DNA or protein was the genetic material. DNA was proven to be genetic material through scientific testing. Genetic material had two jobs: it must duplicate itself and control the development of the rest of the cell in a specific way.- Friedrich Miescher: (1871)o Miescher isolated nuclei from white blood cells. He used pus from bandages from wounded soldiers to get the white blood cells. He found that there was an acidic substance with nitrogen and phosphorous in it Note: an acidic substance is one that has a high level of protons.o This substance was later called nucleic acid.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Archibald Garrod: (1902)o Garrod was an English physician and biochemist. He noticed that a newborn infant’s urine turned black when it was exposed to air. The parents were first cousins. This sort of relationship can result in recessive traits persisting in infants.o There was no staining of the urine at birth and not until the third day after the infant would have consumed and processed breast milk.  This disease was associated with problems later in life: the patient could be prone to severe arthritis. o He was interested in the metabolism of proteins. He knew that the process of phenylalanine took four steps to process. When something went wrong with one step, there would be an excess of the enzyme associated with that step.o A  B  C  D  Eo 1 2 3 4o If enzyme “4” is bad, lots of substance D builds up. Garrod proposes that an enzyme in the process is defective ending in a buildup of the intermediate substance. o This was a different idea of breeding from what people had been doing to get livestock or plants because it was narrowed down to a change in a chemical in the cells.- Hammerling:o Known for his work with grafting algae. He found that the nucleus of the base graft dictated what type of cap the algae would have.- Protein vs. DNA:o Different stains under microscopes shoes both nucleic acid and proteins. Most scientists thought proteins were the genetic material. IT was abundant, and diverse which would explain the diversity of life on earth. They were also simply less familiar with Nucleic Acid.- 1918 Flu:o People were concerned with controlling the spread of the disease. In order to do this they did research on pathogens (they caused the flu).o Frederick Griffith:  He studied pneumonia in mice. Mice could be infected by two strains of pneumonia. The S strain killed the mice so it was virulent and pathogenic,while the R strain didn’t (nonvirulent, nonpathogenic).  S had an outer coating and a smooth appearance, while R had a rough appearance.  Griffith did four experiments:- Mice + R Bacteria = alive mouse- Mice + S Bacteria = Dead mouse- Mice + Heated S Bacteria = live mouse- Mice + (Heated S Bacteria + live R Bacteria) = dead mouse.  In the last experiment, blood tests shoes live s bacteria in the dead mouse.  Why? The R bacteria took something from the heated S bacteria. The R bacteria was transformed by the S. Griffith wanted to know what was taken from them. Was it protein, polysaccharide, nucleic acids, fats?o MacLeod, McCarthy, and Avery  Managed to isolate proteins, Nucleic Acid, Lipids and enzymes. One at a time they add them back to the bacteria, carefully destroying the remnant of biochemical in the extract to make sure they are only adding what they wanted isolated.  The protein they reacted with protease to destroy the protein. The mice died. The protein was not what was killing the mice.  When they reacted DNAse to kill the DNA the mice lived. This showed that the DNA was what was making the mice sick.o Hershey and Chase: They studied simple packages of DNA and proteins, which is what viruses are. These viruses were Bacteriophages (they infected bacteria) The DNA contains phosphorous, and the protein contains a sulphur. Hershey and Chase used radioactive isotopes of Sulfur and Phosphorous to detect whether the protein or the DNA went into the bacteria. Only the DNA with the phosphorous went into the bacteria. - Structure of DNA:o Phoebus Levine: Identified the five carbon sugars (ribose and deoxyribose) Revealed chemical distinction between DNA and RNA (DNA has deoxyribose, RNA has ribose) He also discovered that the three parts of a nucleotide are found in equal proportions: a sugar, a phosphate, and a base. He deduced that one nucleic “piece” or “block” must have one of each of those things.o Chargaff:  In 1950 Chargaff notices regularities in Nucleic acids. A certain percentageof one component of DNA was always equal to another component.  The percentage of A = the percentage of T The percentage of C = the percentage of Go Watson and Crick: Build models and studied X-rays of DNA crystal sto determine the DNA