BIOL-L 211 Lecture 4 Outline of Last Lecture I. Drosophila MelanogasterII. Crossing OverIII. Additional PointsOutline of Current Lecture I. BacteriaA. CharacteristicsB. MicrobiomeC. Bacteria ResearchII. BacteriophageA. CharacteristicsB. Lytic CycleC. Lysogenic CycleD. Bacteriophage ResearchIII. DNAA. CharacteristicsB. Major GrooveC. Minor GrooveD. NucleotidesE. Chargaff's RulesCurrent LectureBacteria and BacteriophageI. BacteriaA. Characteristics1. Prokaryotes, no membrane bound organelles, transcription & translation occur in same location, cell wall of peptidoglycan2. Facilitate easy research in a lab due to features such as: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. Single chromosome (nucleoid)b. Grow fastc. Easy to manipulate3. Functions:a. Cycle Carbonb. Produce Oxygenc. Nitrogen fixationd. Waste decomposition4. May possess: plasmids, flagella, and/or capsulesB. Microbiome1. Human body contains 23,000 genes- 10,000,000,000,000 cells2. Microbiome: bacteria inside humans (in particular in the gut)3. Sense of scale: Microbiome has 3 million genes (among 100 trillion bacteria)4. Probiotics: Bacteria in yogurt (purposely ingested to improve health)5. Applications: Fecal transplants (used to successfully treat clostridium difficile infections) *Seems very nasty, but saves livesC. Bacteria Research1. Frederick Griffith (1928) performed experiments on pneumococcal bacteriaa. Compared two strains (smooth vs. rough); good strain vs. bad strainb. Demonstrated that the heat-killed bad strain could still infect and convert the healthy strain to the bad strainc. The DNA of the S strain converted the R-strain (to the dark side)d. Called this the transformation principle2. Oswald Avery (1944) showed that DNA was the source of genetic material as opposed to proteins/other cell componentsII. Bacteriophage (viruses)- specifically the subset that infect bacteria (hence bacteriophage)A. Characteristics1. Unique genome, capsid//head, occasionally tails2. Two types of bacteriophage:a. Lyticb. Lysogenic/Temperate (know both terms)B. Lytic Cycle1. Phage infects bacterium and injects its genome2. DNA is replicated3. Phage particles are produced4. Bacterium bursts5. Phage ReleasedC. Lysogenic Cycle1. Phage infects bacterium and injects its genome (like Lytic Cycle)2. Phage DNA integrates into bacterium DNA, yielding a "Prophage"3. Prophage is replicated with its new genome4. Cycle may switch to the Lytic CycleD. Bacteriophage Research1. Hershey-Chase Experiment (1952)a. Demonstrated that nucleic acid was the source of the genetic material for phagesIII. DNAA. 2 polynucleotide chains in a double helix structure with both a major and minor groove1. Discovering the double helix: Franklin & Wilkins (1953): X-ray diffraction image of DNA2. Watson & Crick (1953): deduced double helix based off of diffraction image aboveB. Major Groove: location where DNA binding proteins interactC. Minor Groove: location where histone proteins interactD. Nucleotides: composed of a purine//pyrimidine base, sugar and a phosphate group1. Purines: Adenine (A), Guanine (G) (Note: 2 rings)2. Pyrimidines: Cytosine (C), Thymine (T) (one ring)E. Chargaff's Rules:1. A binds with T, G binds with C (with 2 bonds and three hydrogen bonds respectively)2. DNA strands run antiparallel and complementary to each
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