Microorganisms by xU673k

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									Microorganisms
            Microbes

• too small to be seen with the
  naked eye
• aggregations or colonies can be
  seen without the aid of a
  microscope
            Microbes

• are found almost anywhere
• are more abundant than any
  other life form
• they are forms on which all
  others depend.
 Recycle elements required for
             life
• N - Nitrogen
• O - Oxygen
• P - Phosphorus
• S - Sulfur
• C - Carbon
         Microbes produce

• food
• fuel
• air
        4 major categories

• bacteria
• fungi
• protists
• viruses
           Pathogens

• disease causing agents
• AIDS - Acquired Immune
  Deficiency Syndrome
• Botulism - food poisoning
• Tuberculosis
• Polio
          Pathogens
• Typhoid Fever
  Syphilis
            Disease

• Microbes cause disease by
  directly damaging tissues and
  weakening bodily functions or
  by producing toxins that do.
      Pathogenic microbes

• the proportion of pathogenic
  microbes on earth is very small
           Producers

• produce carbohydrates
• break down starch into sugar
• convert sugars into alcohol
   Water Dwelling microbes

• algae and bacteria
• largest producers of carbon
  containing compounds through
  photosynthesis
         Some microbes

• are unable to take in Carbon
  Dioxide from the air.
• They get Carbon from
  bicarbonate in the water
               Ion

• an atom that carries a positive
  (+) or a negative (-) charge
• carries the charge because it has
  gained or lost one or more
  electrons
      Microbes use CHO’s
        (carbohydrates)
• synthesized during
  photosynthesis (Ps) to make cell
  structures and as an energy
  source
• Provide food for larger
  organisms
      Single Celled Fungi

• Yeasts
• Producers in wine making,
  bread baking or beer brewing.
• Convert sugar to alcohol in
  fermentation process
         Cheese Making

• bacteria convert lactose (milk
  sugar) to lactic acid
    Contribute to production

• of food and other substances by
  their enzymes
            Enzymes

• organic molecules that speed up
  biochemical reactions without
  being used up or becoming part
  of the end product.
• A catalyst - causes a reaction to
  take place
            Examples

• foods
• medicines
• vitamins
• leather processing
• textile production
  Decomposers and Recyclers

• world’s greatest recyclers
• Keep elements like C and N
  cycling through the
  environment
• Used to treat sewage, clean up
  toxic wastes, processing
           Recyclers

• more than one type of
  bacterium is needed to convert
  atmospheric N into a form
  useable by plants.
• Requires three different
  chemical reactions.
       Production through
         decomposition
• Methane - decomposition of
  organic matter
• Methanogens - swampy areas,
  land fills, digestive tract of
  ruminants.
       Production through
         decomposition
• Linen fabric is made from flax
  stems
• Stems are immersed in water
• Bacterium digests pectin that
  makes the stalks stiff
    Linen Fabric Production

• remainder is washed dried and
  spun into thread and then
  woven into fabric
     Basic features of MO’s
       (microorganisms)
• 4 major groups
  –bacteria, fungi, protists,
    viruses
• Viruses are not made up of cells
  and are not considered
  organisms by many
   Bacteria, fungi and protists

• have a cellular structure, a
  membrane surrounding
  cytoplasm
             Protists

• have an inner compartment
  nucleus
• DNA in non circular
  chromosomes
• unicellular or multicellular
• protozoans, algae, others
             Fungi

• have cellular structure
• non circular chromosomes
• in fungi with many cells, walls
  between cells are sometimes not
  complete
• cytoplasm and nuclei can
             Fungi

• have cellular structure
• non circular chromosomes
• in fungi with many cells, walls
  between cells are sometimes not
  complete
             Fungi
• cytoplasm and nuclei can
  stream from one cell to another
  within slender filaments of cells
  called hyphae
                Yeasts

• unicellular
             Molds

• have many cells
              Fungi

• visible to the naked eye
  –mushrooms
  –bracts
  –puffballs
  –toadstools
            Viruses

• not cellular
• particles made up of nucleic
  acid and protein
• Include short length of DNA or
  RNA - never both!
              Viruses

• On their own they cannot
  reproduce at all
• Inject their nucleic acid into a
  host cell
             Viruses

• Injected DNA or RNA tricks
  host cell into using the viruses
  chemical instructions to make
  substances needed for the virus
  to reproduce
              Viruses

• Host cell is damaged when
  newly reproduced virus
  particles break out of cell (lyse)
   What does it take to keep a
        microbe alive?
• Lots of variation in
  environmental and nutritional
  condition requirements
        Nutritional needs

• energy sources
• basic elements to make and
  replace cell structures
          Heterotrophs

• organic compounds to meet
  energy needs
• Carbon source to make own
  organic molecules
• get energy from sugars,
  starches, fats and other organic
             Saprobes

• live in soil, get nutrients from
  dead organic matter
• Clostridium botulinum -
  botulism, food poisoning
           Autotrophs

• build their own organic
  compounds if they have an
  available source of inorganic
  compounds
          Phototrophs

• generate their own food using
  sunlight and inorganics such as
  carbon dioxide
          Chemotrophs

• don’t require sun
• get energy from carbon dioxide,
  salts, water and others
    Nitrosomonas bacteria

• live in soil
• use ammonia (NH4) as energy
 hetero, chemo and phototrophs

• use energy from the
  environment
• light and heat energy from the
  sun
• energy stored in chemical bonds
  or organic or inorganic
   Six major elements in cells

• C - Carbon
• H - Hydrogen
• N - Nitrogen
• O - Oxygen
• P - Phosphorus
• S - Sulfur
             Also -

• K- potassium
• Ca - Calcium
• Fe - Iron
• Na - Sodium
       Trace elements

• Co - Cobalt
• Zn - Zinc
• Mo - Molybdenum
• Cu - Copper
• Mn - Manganese
• Si - Silicon
 hetero, chemo, and phototrophs

• some require organic
  compounds that they cannot
  make themselves
• must be added to culture in
  isolation - called growth factors
• Vitamins
  Microbial nutrition in the lab

• hardened gel - called agar
• nutrients are added to the agar
• called growth medium
          Pure Cultures

• Grow only one kind of microbe
• Must use aseptic technique to
  avoid contaminating the culture
         Mixed cultures

• may be grown on selective
  media
• nutritious to some and not to
  others
• allows researchers to isolate a
  certain species of microbe
  Environmental conditions for
       microbial growth
• Oxygen - require Oxygen -
  aerobic
• some microbes live in Oxygen
  poor environment - anaerobic
  Anaerobic processes
• fermentation
• O2 atoms in compounds are
  rearranged and made available
  to microbes
         Anaerobes
• made up of molecules
  containing O2 but don’t
  produce free or gaseous O2
         Anaerobes
• free oxygen may be toxic
              pH
• favorable range - 6-8
• acidophillic - acid loving used
  in mining operations.
• Oxidize Cu, Fe and other metal
  sulfides in the process of
  pulling out the ore
       Temperature
• 37 degrees C (98 degrees F)
• some can survive a wide range
  of temps ranging from 32
  degrees F to 212 degrees F
           Moisture
• dissolve minerals, ions, gases
  and organic compounds
          Moisture
• in extremely dry conditions
  microbes form spores that hold
  the genetic information and
  some cytoplasm.
           Spores
• when moisture is added the
  spore breaks down and bacteria
  resume their normal activity
   Salt concentrations
• most microbes can’t survive in
  high salt or sugar
  concentrations
        Microbe sex
• or - how microbes reproduce
• process is known as binary
  fission
       Binary fission
• increase in size, extend cell wall
  material down center and divide
  in two.
 Speed of reproduction
• in 24 hours some species of
  bacteria can go from one cell to
  16,777,216 cells
  Single celled protists
• have a more difficult
  reproductive process
• DNA in nucleus is fist
  replicated then divided into 2
  identical sets (mitosis)
          continued
• cytoplasm of cell then divides
  to form 2 identical daughter
  cells.
             Fungi
• reproduce by a number of
  methods
• yeasts - budding - cytoplasm
  pinches off on one side of cell
  to form a new cell
• or fuses with another cell
             Fungi
• after fusing with a cell, nuclei
  fuse and divide to form spores
  when released from the cell
             Yeast
• spores become cells on their
  own
    Many celled fungi
• hyphae or filaments fuse to
  form sporagia
• cases in which nuclei from 2
  parent molds excahange pieces
  of chromosomes
• a type of sexual reproduction
 Microbial populations
• can and do change over time
• bacterial populations adapt to
  changes in the environment
          Mutations
• change in DNA
• alteration of base sequence
• occur spontaneously
 Genetic recombination
• exchanging or recombining
  genetic information
• two bacterial cells become
  connected by a thin strand of
  cell material called a pilus
 Genetic recombination
• DNA can travel from one
  microbe to another
• gene enters a microbe that did
  not initially have it

								
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