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Study Objectives for Exam 2 Covering Food Microbiology (Chapters 30 and parts of Chapters 24 (section 24.4) and 16(section 16.5, 16.6, 16.8), Microbial Control (Chapter 5), DNA, Protein Synthesis, Gene Regulation (Chapter 7), and Microbial Genetics/Mutations (Chapter 8 sections 8.1-8.5). Use your lecture notes and the reading guides to help you focus on the most important material covered in these chapters. Use your textbook to read in more details and review exam content identified on this study guide. Chapter 5: Microbial Control 1. What is the difference between bactericidal and bacteriostatic? 2. What is the difference between sterilization and disinfection? 3. How are disinfectants different from antiseptics? 4. How did Joseph Lister and Ignatz Semmelweis contribute to the understanding of microbial control? 5. What parts of an organism are the most sensitive to some type of control? 6. In choosing some type of microbial control, what two main factors are important to consider? Are all organisms equally sensitive? 7. Understand how each of the following physical methods control bacteria: Heat (dry heat, boiling, autoclaving, pasteurization), filtration, freezing, dessication, radiation (ionizing radiation, non-ionizing radiation, and microwaves). 8. Understand how the following types of chemicals control bacteria: Phenol/phenolics, halogens (iodine and chlorine), alcohols, metal compounds (silver, mercury), soaps, quaternary ammonium compounds, and biguanides. 9. What technique would you use to control the growth of organisms in the following situations: -plastic petri plates -drinking water -nutrient agar media -surface of lab benches -open wound/cut -skin before injection -sterilize a heat sensitive solution Chapter 30: Food Microbiology *Also review Chapter 24 (Diseases of the Lower Digestive System) p 644-655, Chapter 16, section 16.5, 16.6, 16.8. 1. Know what the good things bacteria can do to food, the ugly things bacteria do to food, and the bad. 2. What role do the following microbes have in food production: lactic acid bacteria. Yeast, and molds? 3. Understand how these factors can influence microbial growth in foods: temperature, pH, water availability (water activity value aw), atmosphere (O2 available), nutrient content, antimicrobial constituents, and biological structures. 4. What is meant by the terms food borne intoxication and food borne infection? 5. Know how Staphylococcus aureus and Clostridium botulinum cause food poisoning. 6. Understand how the following organisms can cause food poisoning: Campylobacter jejuni, Salmonella enterica, Salmonella serotype Typhi, Salmonella serotype Paratyphi, Shigella, Vibrio cholerae, Vibrio parahemolyticus, Vibrio vulnificus, Listeria monocytogenes, Clostridium perfringens, and the different types of E. coli mentioned in lecture, ETEC, and STEC. For each organism covered in class be able to discuss a. the general characteristics of each organism b. how a person is exposed to the organism (what type of food is the common vehicle?) c. the duration of time before symptoms are seen and the type of symptoms caused by ingestion of the microbe d. the mechanisms of pathogenesis for the organism, any unique toxins made by the organism e. any treatments for the pathogen (don’t worry about specific antibiotics, just whether or not antibiotic therapy would be used) Chapter 7: The Blueprint of Life, from DNA to Protein 1. Know the definition of the following terms: genome, gene, protein, genomics, DNA replication, transcription, and translation. 2. What is meant by the terms genotype and phenotype? 3. What is a gene? What is the relationship between a gene and a protein? 4. Understand all the chemical components found in DNA. Be able to draw a representation of DNA 5. Know the characteristics of DNA and RNA. 6. Be able to explain DNA replication. What is meant by semi-conservative replication? Know the role of all the enzymes involved in the process of DNA replication. 7. Understand the process of transcription. What enzyme is key in the process? Where does it bind to DNA? What forms of RNA can be made in transcription? What happens at each stage of transcription: initiation, elongation, and termination? 8. Understand the process of translation. What happens at each stage: initiation, elongation, and termination? 9. What are the differences between eukaryotic and prokaryotic gene expression? 10. Be able to replicate, transcribe, and translate a sample of DNA. 11. Understand the three ways in which enzyme expression is regulated: enzyme induction, enzyme repression, and constitutive. Know an example of each. 12. Understand how the DNA binding proteins repressors and activators work. 13. Understand how the lactose operon works. What conditions are necessary to turn the operon “on”, what conditions are necessary to turn it “off”? Understand what occurs in reference to the lactose operon to cells growing in the presence of both glucose and lactose. 14. Understand how organisms respond to environmental conditions and alter gene expression through signal transduction, two-component regulatory systems, and quorum sensing. How does natural selection play a role in gene expression? Chapter 8: BACTERIAL GENETICS 1. What is meant by the terms genotype and phenotype? 2. What contribution was made by Barbara McClintock? 3. What is meant by vertical gene transfer? By horizontal gene transfer? 4. Know the definition of a base pair mutation and frameshift mutation. 5. Understand the following terms: silent mutation, missense mutation, and nonsense mutation, auxotroph, and prototroph. 6. What are transposons and how can they contribute to mutations? 7. What are examples of chemical mutagens? Know how they induce changes in the DNA or contribute to the formation of mutations. 8. How do UV radiation and x-rays contribute to mutations? 9. What are the different mechanisms that bacteria can use to repair their damaged DNA? 10. What is meant by direct selection of mutants? Know some examples discussed in class. 11. What is meant by indirect selection of mutants? How does replica-plating work? 12. What is the Ames test? What do you need to run the test, cultures, media, etc. 13. Understand how penicillin enrichment is used to enrich for mutants.