MC3 100 MIDTERMS EXAMS

• Microbial Physiology


  • Impacts of Microbial Metabolism
  • Important Processes
  • Metabolic Diversity
  • Microbial Nutrition
• Impacts of Microbial Metabolism

  • Disease and food spoilage
  • Nitrogen cycle
  • Beverages and food
  • Sewage treatment
  • Drugs
• Important Processes


  1. Carbohydrate catabolism

  2. Respiration

  3. Glycolysis

  4. Krebs cycle

  5. Electron transport chain

  6. Fermentation

  7. Lipid Catabolism

  8. Protein catabolism
• Metabolic Diversity


  • Phototrophs
  • Chemotrophs
  • Autotrophs
  • Heterotrophs

  
• Chemoheterotrophic


  An organism which derives its energy from chemicals, and needs to consume other organisms in order to live
• Microbial Nutrition - Physical Requirements

  • Temperature
  • pH
  • Osmotic pressure
  • Adaptations
• Temperature


  • Psychrophiles - cold-loving
  • Mesophiles - moderate temperature
  • Thermophiles - heat-loving
• Most bacteria grow within a limited range of temperatures, with min and max growth temps only 30° C apart
• Optimum temperature is the temperature at which the species can best grow
• Most bacteria grow best between pH6.5-7.5, and few bacteria grow below pH 4
• When bacteria are cultured in the lab, they often produce acids which interfere with their growth, so chemical buffers are included
• Microbial Nutrition - Chemical Requirements

  • Carbon
  • Nitrogen
  • Sulfur
  • Phosphorus
  • Trace Elements
  • Organic growth factors
  • Oxygen
• Obligate aerobes, Facultative anaerobes, Obligate anaerobes, Aerotolerant anaerobes, and Microaerophiles are different types of organisms based on their oxygen requirements
• Culture Media


  • Nutrient material prepared for the growth of microorganisms
  • Inoculum - microbes introduced to initiate growth
  • Culture - microbes that grow and multiply

  
• Agar


  A solidifying agent that liquefies at 100°C and remains liquid until 40°C, and is not a nutrient
• Forms of Culture Media

  • Broth (liquid)
  • Slants
  • Stab tubes/ deeps
  • Plates
• Broth (liquid)


  Pellicle, Turbidity, Sediment
• Culture media must be initially sterile
• Obtaining Pure Cultures


  Streak plate method
• Preservation


  • Refrigeration
  • Deep-freezing
  • Lyophilization(freeze-drying)
• Five "I"s of Culturing Microbes

  • Inoculation
  • Isolation
  • Incubation
  • Inspection
  • Identification
• Microbial Growth


  Binary fission, Budding
• Sterilization and Anti-microbial Methods

  • Sterilization
  • Disinfection
  • Sanitization
• Aseptic Technique


  • Preventing contamination of a culture with environmental microbes
  • Preventing contamination of yourself or the environment with the organism in the culture
• Control of Growth


  • Moist heat
  • Pasteurization
  • Dry heat
  • Filtration
  • Refrigeration
  • Deep-freezing and freeze-drying
  • High pressure
  • Desiccation
  • Osmotic pressure
  • Radiation
• Disinfection & Disinfectants


  • Phenols and phenolics
  • Biguanides (chlorhexidine)
  • Halogens
  • Alcohols
  • Heavy metals
  • Surface-active agents
  • Aldehydes
  • Chemical sterilization
  • Peroxygens and other oxygen forms
• Unfortunately, few chemical agents achieve sterility; most of them merely reduce microbial populations to safe levels or remove vegetative forms
• Viruses


  • What are Viruses?
  • Viruses and Bacteria Compared
  • Host Range
  • Viral Structure
  • Growing Viruses
  • Viral Taxonomy
  • Viral Multiplication
  • Phage Multiplication: Lytic Cycle
  • Phage Multiplication: Lysogenic Cycle
  • Animal Viruses and Phages Compared
  • Retrovirus Multiplication
  • DNA Virus Replication
  • Multiplication Pathways of RNA Viruses
  • Viruses and Cancer
  • Prions

  
• Viruses


  Obligate intracellular parasites of living but non-cellular nature
• Outside of the cell, viruses are inert
• The majority of viruses are recognized by the diseases they cause in plants, animals and prokaryotes
• Host Range


  Spectrum of host cells the virus can infect, determined by specific host attachment sites and cellular factors

  
• Bacteriophages or phages


  Viruses that infect bacteria
• Important Processes


  • Carbohydrate catabolism
  • Lipid Catabolism
  • Protein catabolism
• Carbohydrate catabolism


  • Glycolysis followed by Krebs cycle and electron transport chain generates 38 ATPs from 1 glucose molecule
  • Fermentation doesn't require Krebs cycle or ETC and produces 2 ATPs from 1 glucose molecule
• Lipid Catabolism


  • Lipids are first broken down into component fatty acids and glycerols by lipases, then each component can enter the Krebs cycle
• Protein Catabolism


  • Proteases and peptidases break down proteins into component amino acids, which must undergo enzymatic conversion into substances that can enter the Krebs cycle
• Metabolic Diversity


  • Phototrophs
  • Chemotrophs
  • Autotrophs
  • Heterotrophs

  
• Chemoheterotrophs


  Organisms which derive their energy from chemicals, and need to consume other organisms in order to live
• Physical Requirements


  • Temperature (Psychrophiles, Mesophiles, Thermophiles)
  • pH
  • Osmotic pressure
  • Adaptations (Extreme halophiles, Obligate halophiles, Facultative halophiles)