Bio 201 1st Edition Lecture 30Outline of Last Lecture I. Sexual Reproduction AdvantagesII. MeiosisIII. Chiasma/Crossing Over/ RecombinationOutline of Current LectureI. Fredrick GriffithII. VirusesA. The Hershey-Chase Experiment Current LectureI. Fredrick Griffith- Scientist that ran an experiment on strains of pneumococcus (Pneumonia) He found that the smooth pneumococcus cells were the strains that led to pneumonia while the rough cells did not. When the S-strain was injected to the mice, they were killed from pneumonia while the R-strain did not kill the mice. -Griffith wanted to create a vaccine for pneumonia so he injected heated S-cells into the mice, this did not kill them, but it did not create an immune response either. Next heinjected heated S-cells with live R, but this caused the mice to die from pneumonia. This was very memorable because the R transformed into S cells even though the S-strain was dead. -So what was this transforming principle? That turned R cells into S cells. -Griffith used the process of elimination to identify the transforming principle, he used enzymes to selectively destroy biological macromolecules. After his tests, he discovered the transforming principle was DNA. II. Viruses- A single virus particle is called a virion. When viruses infect cells, they hijack the host cell machinery to produce more virions. To do so, they must insert their hereditary material into those cells. 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.A. The Hershey-Chase Experiment- (1952) Wanted to know what the hereditary material if viruses is. Steps:1. Radiolabel Viruses: 32p phosphate incorporated mainly into nucleic acids. 35S incorporated only into proteins. 2. Add labeled viruses to bacteria3. Wait for infection4. Use blender to shear virions from extracellular surface of bacteria 5. Differential Centrifugation to separate cells from medium -- cell in pellet, medium in supernatant. Result: YES- DNA is the material of heredity (for viruses at
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