Download Microorganisms

Microorganisms
Modified by Georgia Agriculture
Education Curriculum Office
June, 2002
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