Chapter 7

Chapter 7

1. Essential nutrients of a bacterial cell

   • CHNOPS
   • carbon, oxygen, nitrogen,hydrogen,phosphorus,sulfur

2. Macronutrient

   • required in large quantities, important role in cell structure and metabolism

3. Micronutrient

   • trace elements, present in smaller amounts and sometimes necessary to make proper proteins

4. Organisms energy sources

   • Heterotrophs: obtain carbon in organic form
   • Autotrophs: use inorganic CO2 as carbon source. Able to convert CO2 into organic compounds. Not dependent of others
   • Photoautotrophs: photosynthetic, convert solar energy into chemical energy
   • Chemoautotrophs: use organic compounds for energy and inorganic compounds as a carbon source.
   • Lithoautotrophs: rely only on inorganic minerals and NO sunlight
   • Methanogens: produce methane from CO2 and H2

5. Saprobe:

   • free living microorganisms that feed primarily on organic detritus from dead organisms. They are heterotrophs

6. Parasites:

   • derive nutrients from the cells or tissues of a living host
   • symbiotic( org. live in close nutritional relationships req by one or both members) associations microbes can have with host
     • commensialism: the member called the 'commensal' recieves all of the benefits while the other party is not benefitting or hurting
     • mutualistic:(++) organisms live in a obligatory but mutually beneficial relationship.
     • parasitism: host organism provides the microbe with nutrients and habitat
   • nonsymbiotic (free living relationships not required for survival) relationships microbes can have with host
     • synergism: members cooperate and share nutrients
     • antagonism: some members are inhibited or destroyed by others

7. Diffusion

   • when atoms/molecules move in a gradient from high to low concentration

8. Osmosis

   • diffusion of water through a selectively permeable membrane

9. Isotonic/hypotonic/hypertonic

   • isotonic: environment is = in solute conc. to the cells internal environment
   • hypotonic: solute concentration of the external environment is lower than that of the cells internal environment
   • hypertonic: environment has a higher solute concentration that that of the cytoplasm, brings h2o out

10. Passive transport: energy is not required

    • diffusion
    • facilitated diffusion

11. Active transport: energy required

    • Bulk transport
      • mass transport of large particles or cells through phagocytosis
    • carrier mediated active transport
      • atoms/molecules are pumped into or out of the cell by specialized receptors. Driven by ATP
    • group translocation
      • molecule is moved across membrane and simultaneously made into a metabolically useful molecule

12. 5 bacteria types with temp pref

    • Psychrophiles
      • optimum temp below 15 degrees C
    • mesophiles
      • optimum growth between 20-40 degrees C
    • Thermophiles
      • optimum temp between 45 degrees C to 80 degrees C
    • Hyperthermophiles
      • 80 to 120 degrees C

13. 3 physical factors microbes must contend with

    • Capnophiles: organisms that need a higher CO2 tension
    • Barophiles: deep sea microbes that exist under hydrostatic pressures ranging from 1000 times Atm pressure
    • Alkalinophiles: found in basic conditions
    • halophiles: prefer to live in salty conditions

14. Biofilms

    • antibiotics do not cure them
    • single bacteria attaches to a surface, stimulated to release chemicals.
    • can monitor the cell population size
    • microbes in a biofilm are not free floating like planktonic bact.

15. BINARY FISSION

    • The major way bacteria divide. Meaning one cell becomes two.
    • Parent cell enlarges, duplicates its chromosomes, and then starts to pull its cell envelope together in the center or the cell using a band of proteins. Cell wall forms a septum and this process divides the cell into two daughter cells.

16. BACTERIAL GROWTH CURVE

    • doubling time:the time required for a complete fission cycle, from parent to two new daughter cells.
    • exponential growth: 2 raised to the power of the generation, to figure out the cell pop. 2^2
    • 4 phases
      • 1. Lag Phase
        • cells are freshly inoculated and are adjusting, growing, and synthesizing
      • 2. Exp. growth phase
        • the curve increases geometrically. will continue with proper nutrients and good environ.
      • 3. Stationary phase
        • pop enters a survival mode where cells stop growing or grow slowly.
      • 4.Death phase
        • conditions are toxic and most cells die off but some are still viable
    • can also count bac. with turbidity, colony counts, and direct cell counts

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