1. Pasteur - Final disproof spontaneous generation
2. Hook- Saw first microbes
3. Lister -Aseptic techniques during surgery
4. Semmelweis - Dr. had to wash hands in maternity ward
5. Schultze & Schwann- Chemical treatment of air stops ability to produce life
6. Koch - Developed postulates for disease microbe connection
7. Redi - Maggot-meat experiment
8. Leeuwenhoek - Made first microscope
Fundamental of cells:
Unicellular (Bacteria, Archaea, Protozoa, some fungi) and multicellular organisms (animals and plants)
All cells (prokaryotes + eukaryotes) have in common:
Cell membrane
DNA that holds genetic information
Ribosomes for protein synthesis
Cytoplasm
Eukaryotes are more complex with DNA enclosed in nucleus and membrane enclosed organelles
Bacterial shapes:
Cocci Rods. Vibrio Spirillum
Spirochete Branching Filaments
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, Microbiology Midterm Study Guide
The 5 Is:
Inoculation - Purposely moving something from 1 place to another. starts with specimen collection;
lesion, draw blood, bird droppings, etc.
- introducing a tiny sample into a medium to provide an env't where they multiply.
Incubation - To hear bacteria to make it grow (usually body temp). maintaining something at the most
favorable temperature for its development. 20 deg C & 40 deg. C02 may be required.
- promotes multiplication of microbes over period of hours.
- produces a culture
Isolation - Separate from each other
separation of a strain from a natural, mixed population of living microbes, spreading bacteria apart as far
as possible.
- isolated microbes takes the form of separate colonies on solid media or turbidity (free floating cells) on
broth.
Inspection - Doing tests on the bug
appearance, cells, colony (red? shape, gram stain, sugar, etc.).
Identification - determine type of microbe
- specialized tests; biochemical test to determine metabolic activities specific to microbes
- immunologic tests, genetic analysis.
Microscopy Basics/Types of microscopes:
1. Bright field microscope - Most widely used microscope
image is darker than illuminated field
made by putting light through specimen
2. Dark field microscope- similar to bright field
image is lighter than illuminated field
bright field microscope is changed to dark field microscope by adding a condenser to the light
3. Phase contrast microscope- used with live specimen
produces image with specimen against gray background
can see internal cells
4. Differential interreference microscope- produces colorful 3D image
2 prisms which add contrasting colors to image
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, Microbiology Midterm Study Guide
5. Fluorescence microscope – ultraviolet light for colored image against black field
makes an image
6. Confocal microscope- visualizes fluorescent molecules in a single plane of focus by excluding
out of focus light
7. Transmission electron microscope- uses electron beams to form image
magnify images up to 100,000x
works by transmitting electrons through specimen
8. Scanning electron microscope – detailed 3D images of specimen
magnify up to 650,000x
works by sending electrons to the specimen and detecting deflected electrons is characterized as
a microscope that has lower magnifying power but can provide 3-dimensional viewing of objects.
captures the image of the object in black and white after being stained with gold and palladium.
9. Atomic force microscope- A microscope that uses a beam deflection system with a laser and
photodetector to measure the beam position as a cantilever with a tip scans across the surface of
a material. The force between the tip and sample is calculated by measuring the deflection of the
lever and knowing the stiffness of the cantilever.
10. Scanning tunneling microscope- uses a computer to make highly magnified image of a
specimen
Advantage: can view other objects as small as an individual atom, can view living organisms
Disadvantage: expensive
Light microscopes Vs Electron microscopes:
1. light microscope uses light to illuminate specimens and glass lenses to magnify images.
2. electron microscope uses a beam of electrons to illuminate specimens and magnetic lenses to
magnify images. The resolution (the level of image detailing) is the main difference between these
two microscopes
Resolution:
A scanning transmission electron microscope has achieved better than 50 pm resolution in
annular dark-field imaging mode and magnifications of up to about 10,000,000×
light microscopes are limited by diffraction to about 200 nm resolution and useful magnifications
below 2000×.
Magnification:
Magnification is the ability to make small objects seem larger, such as making
a microscopic organism visible. Resolution is the ability to distinguish two objects from each
other. Light microscopy has limits to both its resolution and its magnification.
Macromolecules key to microbiology:
Macromolecules: Large organic molecules in cells. Includes nucleic acids, proteins, polysaccharides and
lipids
polysaccharide - is one type of macromolecule made up of monosaccharides like glucose and fructose
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