growth of microorganisms
Download
Skip this Video
Download Presentation
GROWTH OF MICROORGANISMS

Loading in 2 Seconds...

play fullscreen
1 / 29

GROWTH OF MICROORGANISMS - PowerPoint PPT Presentation


  • 368 Views
  • Uploaded on

GROWTH OF MICROORGANISMS. Nutritional Classification. Based upon energy and carbon sources Energy source- electron donors Phototrophs (light nourishment) Photosynthesis. Electron Donors. Chemotrophs Oxidation Reduction Breaking & forming bonds. Carbon Source. Autotrophs (self)

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'GROWTH OF MICROORGANISMS' - Thomas


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
nutritional classification
Nutritional Classification
  • Based upon energy and carbon sources
  • Energy source- electron donors
    • Phototrophs (light nourishment)
    • Photosynthesis
electron donors
Electron Donors
  • Chemotrophs
  • Oxidation
  • Reduction
  • Breaking & forming bonds
carbon source
Carbon Source
  • Autotrophs (self)
  • Heterotrophs ( different)
  • Combination of terms
photoautotrophs
Photoautotrophs
  • Energy(electrons) source-light
  • Carbon source-CO2
  • Green & purple Sulfur bacteria
photoheterotrophs
Photoheterotrophs
  • Energy source-light
  • Carbon source –organic cpds
  • Green & purple non Sulfur bacteria
chemoautotrophs
Chemoautotrophs
  • Energy source is oxidation -reduction reactions
  • Carbon source
  • Nitrifying bacteria
chemoheterotrophs
Chemoheterotrophs
  • Energy & carbon source
  • Remove electrons from H in organic cpds
  • Final electron acceptor is oxygen
  • Final electron acceptor is organic cpd
physical requirements for growth
Physical Requirements for Growth
  • Temperature-range
    • Psychrophiles
    • Psychrotrophs
temperature
Temperature
  • Mesophiles-25-40C
  • Thermophiles-50-60C
  • Hyperthermophiles
determination of range
Determination of Range
  • Maximum temperature
  • Minimum temperature
  • Optimum temperature is closer to max
slide13
pH
  • Measures acidity or alkalinity
  • Bacteria grow best at slightly alkaline pH
  • Add buffers to bacterial cultures
  • Molds & yeasts lower pH
osmotic pressure
Osmotic Pressure
  • Microbes need water to grow
  • Use salt/sugar to preserve food
  • Obligate halophiles
  • Facultative halophiles
chemical requirements for growth
Chemical Requirements for Growth
  • Carbon source-50% of dry weight of cell
  • Nitrogen source-amino acids, nucleic acids
minerals
Minerals
  • Trace elements
    • Small amounts of Fe, Zn, Cu, Co etc.
    • Macronutrients-S & P
  • Water-medium for chemical reactions
other growth requirements
Other Growth Requirements
  • Growth factors-essential nutrients
  • E. coli needs no growth factors
other growth requirements18
Other Growth Requirements
  • Buffers
  • A solidifying agent
agar advantages
Agar Advantages
  • Few organisms degrade it
  • Liquefies at 100 C
  • Liquid until 40-50 C
  • Lab-keep liquid at 50 C
  • Once solidified, heat to 100 C
  • Gelatin
    • Nutrient for some organisms
    • Liquefies at 35-37 C
oxygen requirements
Oxygen Requirements
  • Aerobes
    • Use molecular oxygen for respiration
    • Superoxide free radicals (O. -)
    • Superoxide dismutase- must have
    • H2O2 is toxic
oxygen requirements21
Oxygen Requirements
  • Facultative anaerobes
oxygen requirements22
Oxygen Requirements
  • Obligate anaerobes
oxygen requirements23
Oxygen Requirements
  • Aerotolerants
  • Microaerophiles
growth of bacterial population
Growth of Bacterial Population
  • Binary fission or budding
  • Generation time-doubling time
growth curve
Growth Curve
  • Lag phase-preparing to grow
  • Log phase
  • Stationary phase-growth ceases
  • Death Phase
growth of a colony
Growth of a Colony
  • Mass of cells –pure culture
  • Some colonies are distinct
  • Mixture of cells in different phases of growth
growth of a colony27
Growth of a Colony
  • Location within colony determines access to oxygen
  • Surface cells fully aerobic
  • E. coli obtain energy aerobic respiration
  • Embedded cells in center-anaerobic
biofilms
Biofilms
  • In nature, microbes in liquid environment
  • Cells imbedded in extracellular slime
    • Excreted by cells
  • Type of defense mechanism
biofilms29
Biofilms
  • Quorum sensing
  • Important role in infections
  • Soaps & disinfectants
ad