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microbiology 211 > Lab Practical 1 > Flashcards

Lab Practical 1 Flashcards

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Biology 101 flashcards
1
Q

microbial antagonism

A

normal flora compete with harmful bacteriaand prevent them from colonizing in the organism

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2
Q

opportunistic pathogens

A

cause disease in host if there is some weakness in host’s anatomical barriers or immunity
EX: E. Coli

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3
Q

nosocomial infections

A

infections acquired in hospital

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4
Q

types of bacteria

A

coccus-sphere
bacillus-rod shaped
spiral

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5
Q

condenser knob function

A

concentrates light from the illumination source

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6
Q

iris diaphragm knob function

A

adjust the intensity of light

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7
Q

ocular eyepiece lens functions

A

magnify and measure

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8
Q

negative staining

A

quick and does not involve heat fixing
used to identify cell shape; heating causes slight distortion of cell shape
use acidic stains w/ negative charge to stain background
1. drop india ink on end of slide
2. place small amount of m. luteus and mix
3. spread mixture

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9
Q

simple stain

A 
use heat fixing(pass over pilot light)
used to view bacterial size shape or arrangement
highlights the entire organism
use basic stain w/ positive charge
1. heat fix m. luteus
2. flood w/ simple stain and incubate
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10
Q

gram stain

A

groups bacteria due to difference in cell wall
primary stain: crystal violet-turns purple
mordant: iodine-increase binding of primary stain
decolorizer: acetone: removes stain of gram neg
counterstain: safrinin-red color to gram neg
1. E. Coli and S. aureus
2. heat fix
3. flood w/ crystal violet and incubate for 30 sec
4. cover w/ iodine for 1 min
5. acetone 5-10 seconds and immediately rinse
6. cover w/ safrinin for 2 minutes

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11
Q

why don’t acidic background dyes stain bacteria

A

both are negative so repel, staining background

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12
Q

why do basic dyes stain the bacteria

A

dye is positive, bacteria is negative so attract staining bacteria

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13
Q

acid fast staining

A

mycobacterium (mycolic acid in cell wall)
use heat during staining
heat drives carbolfuchsin stain into bacteria through thick waxy lipid in cell wall (mycolic acid)
mycolic acid traps carbolfuchsin and the cells don’t decolorize as easily
mycolic acid is virulence factor
tuberculosis and leprosy
1. e. coli and m. smegmatis- heat fix
2. cut paper towel to fit over slide
3. flood w/ carbolfuchsin and heat over pilot light for 5 minutes
4. remove paper towel and allow to cool then rinse with water
5. decolorize with ACID ALCOHOL for 10 seconds then rinse immediately
6. cover with methylene blue for 2 minutes

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14
Q

virulence factor

A

ability of bacteria to overcome host defenses

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15
Q

endospore staining

A 
use heat to drive malachite green stain through the tough spore coat.
bacillus anthacis
clostridium tetani
clostridium boulinium
1. heat fix b. cereus
2. cut paper towel to fit slide
3. flood paper with malachite green and heat over pilot light
4. allow to cool and rinse w/ water
5. cover w/ safranin for 1.5 min
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16
Q

capsule staining

A

sticky sugary layer around bacteria called capsule
helps bacteria attach to a host and hide from phagocytic cells
capsule is virulence factor
combo of negative stain and simple stain
1. E. coli
2. drop india ink, smear bacteria and smear mixture across slide
3. stain smear w/ crystal violet 1 min
4. gently rinse w water
5. stain w/ safranin for 1.5 minutes

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17
Q

why does a capsule stain require both negative and basic staining?

A

because the negative will stain the background and basic will stain bacterium so the clear part is the capsule

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18
Q

capsule bacteria cause what type of infections?

A

upper respiratory infections

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19
Q

pipette

A

top thing: air to create vacuum
middle thing: suck to suck up liquid
bottom thing: expel liquid

20
Q

aseptic technique procedure

A
  1. mix broth by rolling back and fourth
  2. hold culture in 1 hand and flame loop in other hand and allow to cool
  3. remove cap and hold cap in little finger
  4. pass top of culture tube through blue flame quickly
  5. remove some culture with inoculating loop
  6. reflame top of culture tube through blue flame
  7. cap tube and streak petri plate
21
Q

streak plate testing

A

method to achieve isolated pure colonies

concentrated areas of bacteria are spread out throughout the plate

22
Q

spread plate technique

A

determine amount of bacteria

dilute bacteria, pipette onto agar plate, spread using glass rod

23
Q

why do we consider all the cells of a colony clonal?

A

bc its a population growing from one cell through binary fission

24
Q

CFU

A

colony forming units

25
Q

psychrophiles

A

optimum growth them between 0-20 degrees celcius

26
Q

mesophiles

A

optimum growth them between 20-45 degrees celcius

27
Q

thermophiles

A

optimum growth higher than 55 C

28
Q

why do bacteria have a minimum growth temperature

A

cell membrane fluidity

29
Q

why do bacteria have a max growth temp

A

denature protein and membrane becomes too fluid

30
Q

thermoduric

A

cannot grow at high temps but can survive

endospores

31
Q

acidophiles

A

grow between ph of 0 and 5.5

32
Q

neutrophiles

A

ph range is 5.5-8

33
Q

alkalophiles

A

ph between 8 and 11.5

34
Q

why do bacteria have a minimum/maximum growth ph

A

bc denatures proteins and affects hydrogen bonding

35
Q

hypotonic environment

A

low solute, high water content=water moves into cell

36
Q

hypertonic environment

A

high solute, low water content= water moves out of cell

37
Q

isotonic environment

A

concentration is the same=no net gain or loss of water

38
Q

which solution will have the greatest effect on a bacterial cell? why?

A

hypertonic bc plasmolisis occurs, pulling the cell wall

39
Q

plasmolysis

A

removes necessary water from a cell by pulling the plasma membrane away from the cell wall, and inhibiting the growth of the cell.

40
Q

obligate aerobes

A

grow only in the presence of oxygen (bacteria growth on top)

41
Q

facultative anaerobes

A

can grow with or without oxygen, but prefer oxygen (growth on top but coming down)

42
Q

obligate anaerobes

A

killed by oxgen (growth on bottom)

43
Q

aerotolerant anaerobes

A

do not use oxygen for growth but are not harmed by it (growth throughout tube)

44
Q

microaerophiles

A

require less than atmospheric concentrations of oxygen (growth in middle)

45
Q

bacteriostatic

A

antibiotic inhibits growth (fuzzy ring)

46
Q

bacteriocidal

A

kills bacteria (very defined zone of inhibition)

microbiology 211 (6 decks)

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