Crawford- Microbiology Study Tool by Abbigail Crawford https://padlet.com/acrawford244/zd40joe872x3yycq en-us 2022-09-11 15:44:09 UTC 2025-11-19 14:56:37 UTC hello@padlet.com Review of Cells- acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291228172 Cells are the simplest unit of living matter.

Cell Theory-
1. All living organisms are composed of cells. They may be unicellular or multicellular.
2. The cell is the basic unit of life.
3. Cells arise from pre-existing cells.]]> 2022-09-11 15:46:57 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291228172 Prokaryotes vs Eukaryotes acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291229541 Prokaryotes-
  • Simple, no nucleus or membrane-bound organelles
  • Bacteria and Archaebacteria
  • Grow and reproduce commonly through asexual reproduction - binary fission
  • Typically rod, spherical, or corkscrew shape
Eukaryotes-
  • Complex, membrane-bound organelles
  • Protists, plants, fungi, animals
  • Grow and reproduce via mitosis or meiosis
]]> 2022-09-11 15:49:23 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291229541 Prokaryotic Metabolism acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291231488 Autotroph-
  • Carbon is obtained directly from CO2
  • Photoautotroph- Light
  • Chemoautotroph - inorganic oxidation (of water, minerals, nitrogen gas)

Heterotroph-
  • Carbon is obtained from other things (not directly CO2)
  • Photoheterotroph - Energy from light
  • Chemoheterotroph - depend on organisms for carbon

]]> 2022-09-11 15:52:08 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291231488 Prokaryotic Metabolism acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291233324 2022-09-11 15:54:34 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291233324 Prokaryotes- Reproduction acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291233785
  • Genetic Transfer/Bacterial Conjugation
    • Prokaryotes can grab stray DNA from environment
    • Plasmid transfer***
  • This is how prokaryotes get variation!
    • Antibiotic resistance, new virulence factors, diversity
  • Binary Fission
    • Rapid reproduction of 2 identical daughter cells
    • ]]>     2022-09-11 15:55:19 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291233785     Eukaryotes- Reproduction acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291234471 Cell Cycle
    • Mitosis
      • Somatic/Body cells
    • Meiosis
      • Gametes
      • Egg/Sperm
    • Variations & Diversity come from mutations

    ]]>     2022-09-11 15:56:15 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291234471     Fermentation acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291234909
  • Fermentation: A natural metabolic process in which microorganisms convert carbohydrates into byproducts such as alcohol, Carbon Dioxide, or acid.
    • It is an anaerobic process (aka - without oxygen)
    • Can be prokaryotic or eukaryotic cells!
    • Lactobacillus - breaks down lactose into lactic acid
    • Saccharomyces (a fermentative yeast) - helpful for bread and alcohol
    • Penicillium (a fermentative mold) - preserves shelf life of dairy and meat products
    • ]]>     2022-09-11 15:56:54 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291234909     Microbial Taxonomy- The Prokaryotes acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291236330 Bacteria- 
    • Unicellular
    • May possess a flagella for movement
    • Aerobic (live in O2)
    • Anaerobic (can’t live in O2)
    • Facultative (An)aerobe (lives in either environment)
    • Gram + or Gram - (depends on peptidoglycan in cell wall)
    Archaea-
    • Unicellular
    • Live in extreme environments
    • Thermophiles (extreme hot temps)
    • Halophiles (salty environment)
    • Methanogens (methane-producing)
    • Psychrophiles (extreme cold)

    ]]>     2022-09-11 15:59:04 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291236330     Microbial Taxonomy- The Eukaryotes acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291237431 Protozoa-
    • Aerobic eukaryotes
    • Cellulose in cell wall
    • Many ways of locomotion (movement)
      • Cilia (hair-like)
      • Flagellates (whip-like)
      • Pseudopodia(fake feet)
    Algae-
    • Unicellular or multicellular
    • Cyanobacteria or blue-green algae
      • Photosynthetic
    • Live in damp soil, water, and on rocks
    ]]>     2022-09-11 16:00:54 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291237431     Microbial Taxonomy- Fungi acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291238380 Fungi- 
    • Mushroom, molds, yeast
    • Cell wall contains chitin
    • Reproduce by releasing spores
    • Decomposers
    ]]>     2022-09-11 16:02:17 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291238380     Microbial Taxonomy- Viruses acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291239421 Viruses-
    • Non-living, non-cellular entities
    • Consist of: 
      • DNA or RNA (nucleic acid)
      • Surrounded by a protein coat
    • Require a host to reproduce
    ]]>     2022-09-11 16:03:36 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291239421     Microbial Taxonomy- The Helminths acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291242686 Helminths-
    • Not technically microorganisms, but part of their life cycle is microscopic
    • Flatworms
    • Lung Fluke Disease (Paragonimiasis)
    • Roundworms
    • Ascariasis (infection of small intestine)
    Their parasitic tendencies are important for clinical reference
    ]]>     2022-09-11 16:08:50 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291242686     Bacterial Shapes acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291243993 Bacilli-Rod-shaped, Important Examples: Streptobacillus, Bacillus
    Cocci-Round, spherical, Important Examples: Staphylococci, Streptococci

    ]]>     2022-09-11 16:11:02 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291243993     Bacterial Shapes acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291245281 Spirilla- Rigid spiral-shaped bacteria
    Filamentous- Thread-like, cells elongate but don’t divide


    ]]>     2022-09-11 16:13:11 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291245281     Gram Staining acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291247209
  • Add crystal violet stain
  • Add iodine
  • Rinse gently with ethyl alcohol
  • Counterstain with safranin
  • Gram + will be violet/blue
  • Gram - will be pink/red

    • Gram  +:
    Thick,     peptidoglycan layer

    Gram -:
    Thin/no,     peptidoglycan layer
    ]]>     2022-09-11 16:15:21 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291247209     acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291248504 2022-09-11 16:17:11 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291248504 acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291248847 2022-09-11 16:17:45 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291248847 Identifying AEROBIC Bacteria- Catalase Test acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291250033
  • Catalase: Enzyme produced by bacteria that uses oxygen
  • A positive catalase test will have bubbles present
  • A negative catalase test will have no reaction
    • ]]>     2022-09-11 16:19:46 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291250033     Identifying AEROBIC Bacteria- Thioglycolate Test acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291250482
  • Obligate Aerobic: Love O2
  • Obligate Anaerobic: Avoid O2
  • Facultative: Prefer O2, but not hurt by the lack of O2
  • Microaerophiles: Low O2 levels
  • Aerotolerant: They do not care

    • ]]>     2022-09-11 16:20:35 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291250482     Factors that Affect Bacterial Growth acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291251242
  • Space, Waste
  • Nutrients, Temp
  • pH & gas concertation 
  • Water
    • ]]>     2022-09-11 16:21:54 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291251242     Viruses- Structure acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291252059
  • Consists of a nucleic acid
    • DNA or RNA
    • This is its genetic material
    • Single or double stranded
  • Outer layer is the... 
    • Capsid: rigid structure to withstand harsh environments.
    • Envelope: can only survive in aqueous solutions (usually transmitted via fluids)

    • ]]>     2022-09-11 16:23:16 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291252059     Viruses- Structure acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291252452 COVID...
    • Envelope
      • No capsid
      • Transmits via fluids
    • Single stranded RNA
    • Spherical
    ]]>     2022-09-11 16:23:50 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291252452     Viruses- Shapes acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291252801
  • Complex, 
    • Bacteriophage: A virus that infects bacteria)
  • Helical/Filamentous 
    • Tobacco mosaic virus, Ebola
  • Spherical
    • COVID-19, Influenza, Hepatitis B and C
    • Enveloped
  • Polyhedral
    • Poliovirus, adenovirus, rhinovirus
    • ]]>     2022-09-11 16:24:10 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291252801     Chain of Infection: acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291253823 Organism → Reservoir→ 
    Portal of Exit→ Transmission → Portal of Entry→ Susceptible Host


    ]]>     2022-09-11 16:25:28 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291253823     Spread of Infection acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291254618 Airborne- Long distance, remain suspended in air up to 6ft - Measles, TB, Chickenpox
    Vector-Borne- Transfer from host (carrier) → victim- Malaria (mosquitoes)
    Common Vehicle- Transfer by contaminated source - Salmonella
    Droplet- Close proximity, coughing, sneezing, talking - Pertussis, Flu, TB
    Direct Contact- Person/Person, Animal/Person, Pregnancy - Rabies, HIV, Ebola, Lice, STDs]]>     2022-09-11 16:26:50 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291254618     Virulence Factors acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291255786
  • Invade the host
  • Cause disease
  • Evade host defenses

    • Adherence Factors- Bacteria use pili to stick to cells
    Invasion Factors- Allow easier invasion of host cell - coded in plasma
    Capsules- Protection - resistant to phagocytosis
    Endotoxins-     On Gram Negative bacteria - released when cell dies
    Exotoxins- Secreted     - neurotoxins, cytotoxins, enterotoxins
    Siderophores- Iron binding factor - competes host for iron, Hemoglobin uses iron to carry O2
    ]]>     2022-09-11 16:28:40 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291255786     What Medication Would We Use? acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291258414 Antibiotics
    • Used for a BACTERIAL infection
    • Common Bacterial Infections: Bronchitis, ear infections, UTIs
    • Common Antibiotics: Doxycycline, Penicillin, Amoxicillin
    Antivirals
    • Used for a viral infection
    • Common Viral Infections: Influenza, HIV, Herpes
    • Common Antivirals: Tamiflu, Retrovir, Zovirax
    ]]>     2022-09-11 16:33:24 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291258414     How Do We Grow Bacteria? acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291258703
  • First, we need to make sure we practice aseptic technique.
  • Second, we need a media to grow them on.
  • Third, we’ll need to wipe surfaces with a sterile applicator (looks like a really long Q-Tip or cotton swab).
  • Fourth, we would inoculate the agar plate using a spreading technique.
  • Fifth, wrap plates in parafilm and incubate 48-72 hours!
    • ]]>     2022-09-11 16:33:51 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291258703     What's A Media? acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291259708 Nutrients for Microbes- Different media can have different nutrients that grow specific bacteria
    Different Kinds-
    • LB Agar
    • YMA
    • Potato Dextrose
    • MacConkey Agar
    • Sheep’s Blood
    Identification- Narrowing down growth allows microbiologists to identify their cultures

    ]]>     2022-09-11 16:35:20 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291259708     Types of Agar acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291261577 LB Agar- Common, Not very selective
    Potato Dextrose-     Grows both bacteria and fungi
    Yeast-Mennitol-     Used for soil microbiology
    Sheep's Blood-  Determines type of hemolysis (breaking down blood)
    MacConkey- Selects for Gram (-) bacteria and lactose fermentation]]>     2022-09-11 16:38:16 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291261577     Hemocytometer acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291262796
  • Used to count the number of cells in a sample under the microscope
  • Trypan Blue: A dye that exclusively labels dead cells to differentiate them from live cells
  • Cells that are white (not filled in with blue) are live cells!
  • Solid blue cells are dead cells.
  • Equation for Total Viable Cells: (Average Viable Cells) x 10,000 x DF
    (DF = Dilution Factor)

    • (Average Viable Cells) x 10,000 x DF
    • Q1: 20 white, 3 blue
    • Q2: 20 white, 2 blue
    • Q3: 20 white, 2 blue
    • Q4: 21 white, 3 blue
    • DF = 5
    ((20+20+20+21)/4) x 10,000 x 5 20.25 x 10,000 x 5 = 1,012,500 viable cells
    ]]>     2022-09-11 16:39:06 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291262796     Preparing the Petri Dish acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291263894
  • Always read directions on how to prepare the agar!
  • On the petri dish, write this on the agar side:
    • Your Name
    • Date
    • Time
    • Sample (Example: Ms. Fusco’s door handle)
  • DO NOT WRITE ON THE Lid

    • ]]>     2022-09-11 16:40:45 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291263894     Plating Techniques acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291264100 METHOD 1: Triple-Z- This should give you isolated colonies. 
    1. Draw T on bottom of plate.
    2. Flame sterilize inoculating loop, let cool 10 seconds
    3. Pick up culture with loop.
    4. Streak like a z-method back and forth in quadrant 1. DO NOT CROSS your T.
    5. Flame sterilize and let cool
    6. Drag inoculating loop through the end of quadrant 1 into quadrant 2.
    7. Keep streaking in quadrant 2 with a z pattern. DO NOT CROSS ANY T again. 
    8. Flame sterilize, let cool
    9. Drag inoculating loop through the end of quadrant 2 into quadrant 3.
    10. Keep streaking in quadrant 3 with a z pattern. DO NOT CROSS the T again. 

    METHOD 3: 4-Quadrant Streak
    1. Sterilize loop, let cool for 10 seconds
    2. Pick up desired colony and spread horizontally in Quadrant 1.
    3. Sterilize loop, let cool for 10 seconds.
    4. Overlap Quadrant 1 and spread horizontally in Quadrant 2.
    5. Repeat steps 3&4 for Quadrants 3 and 4.

    Incubation: 
    1. Wrap parafilm around the edges of the petri dish.
    2. Place dish into incubator (can stack dishes to save time).
    3. Make sure plates are turned upside down!
      • Why???

    ]]>     2022-09-11 16:41:06 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291264100     Plating Viruses acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291265481
  • Can be cultured, but it looks a little different
  • Viruses can be grown in vivo (inside a whole living organism) or in vitro (in a test tube, agar plate, cell culture flask)
  • On agar plates: Bacteriophages need a bacterial lawn first! They will not grow without any cells to infect.
    • ]]>     2022-09-11 16:43:12 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291265481     How To Do A Gram Stain acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291265818
  • Add one drop of distilled water onto a slide.
  • Put a loopful of the desired bacteria colony into that drop (you do not need the entire colony - too much will crowd your stain).
  • Fix culture onto a slide using a flame (wave it over the flame, never HOLD it over).
  • Add a drop of crystal violet onto the sample and let sit for 20 seconds.
  • GENTLY rinse the slide with distilled water or you’ll lose your sample.
  • Add a drop of iodine and let sit for 20 seconds.
  • GENTLY rinse the slide with distilled water or you’ll lose your sample.
  • Add a few drops of decolorizer (acetone/ethanol) and let it run off the slide. Rinse with water after 5 seconds.
  • Counterstain with fuchsin for 40-60 seconds then rinse off with water.
  • Gently shake of excess water and let air dry. 
  • Look under microscope
  • Blue stain: Gram-positive
  • Red stain: Gram-negative
    • ]]>     2022-09-11 16:43:44 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291265818     How To Do A Catalase Test acrawford244 https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291266690
  • Put a sample colony onto the slide using an inoculating loop.
  • Add one drop of hydrogen peroxide and look for bubbles.
  • Bubbles = catalase positive (catalase is present).
  • No bubbles = catalase negative (no catalase is present).

    • ]]>     2022-09-11 16:44:50 UTC https://padlet.com/acrawford244/zd40joe872x3yycq/wish/2291266690