Lab exam 2

• What are the three environmental conditions bacteria encounter?

  -different temperatures, pH levels, and osmotic pressures
• What are cardinal temperatures?

  -minimum, optimum, and maximum temperatures at which an organism can grow
• What is normal body temperature?

  98.6 degrees Fahrenheit (37 degrees Celsius)
• What are psychrophiles?


  only grow in temps LESS than 20 degrees C (-5 to 20 C)

  -NOT human pathogens
• What is the range of growth for psychrotrophs?Where are they found?

  0-30°C

  -soils, surface water and in foods

  -CAN be human pathogens
• What range do mesophiles grow?

  15-40 C (optimal = human body temp)

  -can be human pathogens
• Range for thermophiles?


  40-75 C
• Range for Extreme thermophiles/hyperthermophiles?Found?

  65-110 C

  -hot springs and ocean floor vents/ridges respectively
• What is pH?


  -concentration of H+ ions in a solutions

  -measured on logarithmic scale from 0-14
• What pH is a acidophile, neutrophile, and alkaliphile?

  acidophile: <4.5-5.5 neutrophile: 5.5-8 alkaliphile: >8-8.5
• Turgor Pressure


  the pressure inside a cell that is required for survival
• Lysis


  cell rupture
• Plasmolysis


  cell shrinkage
• Osmosis


  movement of water from low solute concentration to area of high solute to achieve equilibrium
• Osmotic pressure


  force of water going through osmosis
• Qualities of Hypotonic solution

  -low osmotic pressure

  • water moves INTO cell
  • cell WILL lysis
• qualities of isotonic solution

  -equal concentrations

  -water moves in and out of cell at equal rates
• Qualities of hypertonic solutions

  -high osmotic pressure

  -water moves out of cell

  -cell will plasmolysis
• What are the three solution types a bacteria could encounter?

  Hypertonic, hypotonic, isotonic.
• Salinity


  salt concentration in solution
• What are halophiles?


  salt loving bacteria
• Extreme halophiles


  only survive at salt conc. of 15-25%
• Osmotolerant bacteria


  bacteria that survives/grows in wide rang of salt concs
• AEROTOLERANCE


  the ability or inability to live in the presence of O2
• OBLIGATE AEROBES


  requires oxygen for growth/survival
• FACULTATIVE ANAEROBES


  can grow in the presence OR absence of Oxygen
• AEROTOLERANT ANAEROBES


  do NOT need O2 BUT can survive in the presence of O2
• MICROAEROPHILES 


  survive ONLY when O2 levels are low
• CAPNOPHILES


  survive ONLY when CO2 levels are high
• OBLIGATE ANAEROBES


  ANY O2 will KILL the bacteria
• What does a reducing agent do? examples?

  reduces O2 to H2O

  -Na thioglycolate and L-cystine
• What color does an oxidation-reduction indicator turn? Example?

  -red/pink in presence of O2

  -straw color in absence of O2

  -Resazurin
• Where do aerotolerant anaerobes grow in a tube?

  all throughout the tube
• Where do facultative anaerobes grow in a tube?

  Throughout the tube
• Where do obligate anaerobes grow in a tube?

  At the bottom.
• Where do obligates aerobes grow in a tube?

  At the top
• How does a CHEMICAL GAS GENERATING PACKET get activated?

  exposure to air; produces CO2 gas
• Color indicators/meanings of METHYLENE BLUE INDICATOR STRIP OR TABLET?

  -blue in the presence of O2• white in the absence of O2
• Common reasons why anaerobic conditions were not achieved?

  -incomplete gasket seal

  -hole
• Where is most anaerobic bacteria work conducted?

  anaerobic chamber