Microbiology Topics Reviewer PDF

Reviewer for Microbiology Topics ▪ Missense: Changes amino Microbial Metabolism acid. 1. Catabolism vs. Anabolism:...

Reviewer for Microbiology Topics ▪ Missense: Changes amino Microbial Metabolism acid. 1. Catabolism vs. Anabolism: ▪ Nonsense: Introduces a stop o Catabolism: Breakdown of molecules codon. to release energy (e.g., cellular 3. Horizontal Gene Transfer: respiration). o Transformation: Uptake of naked o Anabolism: Building of molecules DNA. using energy (e.g., synthesis of o Transduction: Gene transfer via macromolecules). bacteriophages. 2. Energy Production Pathways: o Conjugation: Transfer of plasmids o Glycolysis: through a pilus. ▪ Converts glucose to pyruvate. 4. Genetic Engineering: ▪ Produces ATP and NADH. o Use of plasmids in recombinant DNA o Citric Acid Cycle (Krebs Cycle): technology. ▪ Produces NADH, FADH2, and o Example: Producing insulin using ATP. genetically modified bacteria. ▪ Releases CO2. o Electron Transport Chain (ETC): Review Questions: ▪ Uses NADH and FADH2 to What enzymes are involved in DNA generate a proton gradient. replication, and what are their functions? ▪ Produces ATP via oxidative Compare and contrast the mechanisms of phosphorylation. transformation, transduction, and conjugation. 3. Fermentation: How can mutations affect bacterial survival o Occurs in the absence of oxygen. and adaptation? o Produces ATP and byproducts (e.g., How are plasmids used in biotechnology? lactic acid, ethanol). 4. Aerobic vs. Anaerobic Respiration: Microbial Growth Control o Aerobic: Oxygen is the final electron 1. Sterilization acceptor. Definition: The complete elimination or o Anaerobic: Uses other molecules destruction of all forms of microbial life, (e.g., nitrate, sulfate) as acceptors. including bacteria, viruses, fungi, and spores. 5. Microbial Enzymes in Metabolism: Methods: o Examples include catalase, o Physical: Heat (autoclaving, dry superoxide dismutase, and amylase. heat), radiation (gamma or UV). 6. Biochemical Tests Related to Metabolism: o Chemical: Use of sterilizing agents o Examples: Sugar fermentation test, (e.g., ethylene oxide, hydrogen methyl red test, citrate utilization test. peroxide gas). Application: Medical instruments, surgical Review Questions: tools, laboratory equipment, culture media. What is the main difference between aerobic Effectiveness: Kills all microorganisms, and anaerobic metabolism? including resistant spores. Why is glycolysis considered a universal 2. Disinfection pathway? Definition: The process of eliminating most How does the ETC generate ATP? pathogenic microorganisms, but not Which biochemical test would you use to necessarily all microorganisms, from identify fermentative bacteria? inanimate objects or surfaces. Methods: Chemical disinfectants (e.g., bleach, Microbial Genetics alcohol, phenolic compounds), UV light, or 1. DNA Structure and Replication: heat (boiling). o DNA is double-stranded and follows Application: Surfaces in hospitals, kitchens, complementary base pairing (A-T, G- bathrooms, or laboratories. C). Effectiveness: Does not eliminate bacterial o Enzymes: DNA polymerase, helicase, spores and may not be effective against all ligase. viruses. 2. Mutations: 3. Antisepsis o Point Mutation: Single base change. Definition: The process of inhibiting or o Frameshift Mutation: Addition or destroying microorganisms on living tissues to deletion of bases, altering the reading prevent infection. frame. Methods: Antiseptic solutions or compounds o Missense vs. Nonsense Mutations: (e.g., iodine, alcohol, hydrogen peroxide).  Application: Skin disinfection before surgery, treating wounds, hand sanitizers. 3. Filtration Effectiveness: Safe for use on living tissues ▪ Air Filtration: HEPA filters to remove but generally less potent than disinfectants. microorganisms from the air. 4. Degerming ▪ Liquid Filtration: Used for heat-sensitive Definition: The physical removal of dirt, oil, liquids or gases (e.g., antibiotics). and microorganisms from the skin or other ▪ Effectiveness: Physically removes surfaces, usually through mechanical means. microorganisms from liquids and air, does Methods: Scrubbing, washing with soap, or not kill them. using an antiseptic. Application: Handwashing, cleaning skin 4. Desiccation (Drying) before injections. Effectiveness: Deprives microorganisms of Effectiveness: Reduces microbial load, but water, causing them to become inactive. Some does not sterilize or disinfect. microorganisms (e.g., spores) are more 5. Sanitation resistant to desiccation. Definition: The process of reducing microbial populations to a level considered safe by 5. Cold Temperature public health standards, usually on surfaces or ▪ Refrigeration: Slows microbial growth by in environments. lowering temperatures. Methods: Cleaning with detergents, ▪ Freezing: Stops microbial growth but does disinfectants, or sanitizers. not kill all microorganisms. ▪ Effectiveness: Effective in slowing down Application: Food preparation areas, public microbial metabolism; freezing may kill restrooms, hospitals. some microbes (e.g., parasites) but may Effectiveness: Reduces pathogens to safe not be effective against all. levels, but does not eliminate all microorganisms. Chemical Agents 1. Disinfectants Physical Agents Alcohols (e.g., ethanol, isopropyl alcohol): 1. Heat Denature proteins, dissolve membranes. ▪ Moist Heat: More effective than dry heat. It Common for surface disinfection and hand denatures proteins and disrupts cell sanitization (70-90% concentration). membranes. ▪ Autoclaving: High-pressure steam at 121°C Halogens (e.g., chlorine, iodine): Disrupt cell for 15-20 minutes (sterilization). walls, proteins, and DNA. Chlorine is used for ▪ Boiling: Usually 100°C for 10-30 minutes water treatment, iodine for skin disinfection. (disinfection). Phenolics (e.g., phenol, Lysol): Disrupt cell ▪ Pasteurization: Mild heating to kill pathogens membranes and proteins. Effective for without affecting taste/quality (e.g., milk at 63- surfaces in healthcare settings. 72°C for a few minutes). Aldehydes (e.g., formaldehyde, ▪ Dry Heat: Requires higher temperatures and glutaraldehyde): Inactivate proteins and longer exposure times. nucleic acids. Used for sterilizing equipment. ▪ Hot Air Oven: Used for sterilizing glassware, Effectiveness: Varies by concentration, instruments (160-180°C for 1-2 hours). microorganism type, and application method. ▪ Effectiveness: Kills microorganisms by Typically used for disinfection, but not always denaturing proteins, disrupting membranes, sterilization. and causing dehydration. Moist heat is more effective than dry heat. 2. Antiseptics Alcohols (e.g., ethanol, isopropyl alcohol): 2. Radiation Used on living tissue for skin disinfection. ▪ Ionizing Radiation (Gamma rays, X-rays): Iodine and Iodophors (e.g., Betadine): Used High-energy radiation that causes DNA in wound care and pre-surgical cleaning. damage, sterilizing medical equipment, food, Hydrogen Peroxide: Used for cleaning and pharmaceuticals. wounds and as an antiseptic. ▪ Non-ionizing Radiation (UV light): UV-C light Chlorhexidine: Used in medical settings for causes DNA damage, used for surface cleaning skin before surgery and as a sterilization, air purification, and water mouthwash. treatment. Effectiveness: Safe for use on living tissues, ▪ Effectiveness: Ionizing radiation can sterilize, reduces microbial load but typically does not while non-ionizing (UV) is useful for sterilize. disinfection but cannot penetrate surfaces effectively.  3. Sterilant o Examples: HIV (retrovirus), Influenza Ethylene Oxide: Gas sterilization for heat- (RNA virus), Hepatitis B (DNA virus). sensitive medical equipment (e.g., plastic 4. Vaccination and Antiviral Strategies: items, surgical tools). o Stimulate immune system to Hydrogen Peroxide Vapor: Used in recognize and combat viruses. vaporized form for sterilizing hospital rooms o Examples of vaccines: MMR and medical devices. (measles, mumps, rubella), HPV. Formaldehyde: Sometimes used in cold 5. Virus Detection Methods: sterilization techniques. o Examples: PCR, ELISA, cell culture Effectiveness: Strong enough to sterilize, techniques. used for items that cannot withstand heat. o Question: What are the advantages of using molecular techniques like PCR? 4. Surfactants (Detergents) Soaps and Detergents: Mechanical removal of microbes by emulsifying oils and fats, often used in cleaning. Effectiveness: Helps remove dirt and oils but doesn't necessarily kill microbes. Reduces microbial load through physical action. 5. Heavy Metals Silver Nitrate, Mercury compounds, Copper Sulfate: Disrupt cell function and are used for wound care, eye drops for infants, and water treatment. Effectiveness: Can be toxic to both microorganisms and human cells, limiting their use. Factors Affecting Control: Number of microbes, exposure time, type of microbial structure (e.g., spores). Applications in Daily Life: Use of autoclaves in medical settings. Hand hygiene: Importance of soap and alcohol-based sanitizers. Review Questions: Why are spores harder to kill than vegetative cells? How do UV light and ionizing radiation differ in their microbial control mechanisms? Why is it important to follow specific sterilization times and temperatures? Viruses 1. Characteristics of Viruses: o Non-living, acellular infectious agents. o Components: Capsid, genetic material (DNA or RNA), envelope (in some viruses). 2. Viral Life Cycle: o Lytic Cycle: Virus replicates and lyses the host cell. o Lysogenic Cycle: Viral DNA integrates into the host genome. 3. Types of Viruses: o DNA viruses, RNA viruses, retroviruses.