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Flashcards in Principles of Micro 2 Deck (40)
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1

describe the experiment by Louis Pasteur

he did the experiment with the swan neck flask where he boiled broth to get rid of all the microorganism and it stayed sterile because microorganism were trapped in the neck of the flask

2

what happened to the broth when the neck of the flask was broken

it became contaminated once exposed to the air

3

describe the work of Robert Koch

he wanted to figure out how disease occurred using pure culture from a diseased mice and infecting a healthy mice

4

what are Koch's postulates

1. the suspected causative organisms should always be present with the specific disease and absent in healthy animals
2. the suspected organism can be grown in pure culture
3. organisms taken from pure culture should cause disease in healthy animal
4. the suspected organism can be re-isolated and shown to be the same as the original

5

what were problems with Koch's postualtes

-not all microorganisms are culturable
-some microorganisms are opportunistic - so they can be present in a healthy individual and not cause disease unless under the right conditions
-re-isolated microorganisms might not be the same as original

6

who is John Snow

-father of epidemiology
-showed contaminated pump handles were contaminating water causing cholera

7

who is Edward Jenner

-he inoculated a young boy with cowpox to create immunity against smallpox
-brought about the concept of vaccination

8

what is Ignaz Semmelweiss known for

washing hands between patients can reduce incidence of infections (though his idiot companions paid him no mind)

9

describe the work of Anthon von Leeuwenhoek

he came up with the early microscope

10

what is magnification, resolution, and resolving power

magnification - enlarging of object
resolution - degree to which detail is maintained in object
resolving power - minimum spacing between two points where can be clearly as separate entities

11

factors the limit microscopic magnification of microorganisms

resolution, resolving power, wavelength

12

light source and max magnification for brightfield

visible
1500x

13

light source and max magnification for fluorescence

UV
1500x

14

light source and max magnification for TEM

electrons
500,000 - 1,000,000 x

15

light source and max magnification for SEM

electrons
10,000 - 1,000,000x

16

what are two different ways to prep specimen for microscopic viewing

-placing live specimen on surface then putting a coverslip

-kill specimen then put coverslip

for both preparation one can put dye or stain

17

when will one use a live vs. killed specimen

live: motility, cell behavior, short term

killed: physical appearance, longer term storage

18

what does the positive stain stick to

-the actual specimen providing color
-basic (neg aspect)

19

what does the negative stain stick to

-settles around the specimen to form a silhouette so sticks to the background
-acidic (positive)

20

what color does the gram positive and gram negative stain

gram + - purple
gram neg - pink

21

when does one gram stains

for some bacterias but it can't stain all

22

what is Paul Ehrlich known for?

the stain method called acid fast - ziehl neelsen method

23

how does the acid fast-ziehl neelsen method work

carbol fuschin --> heat five mins --> decolourise --> methylene blue

24

what are the colors of the stain in acid fast-ziehl neelsen method

the acid-fast bacteria stains pink/red
while the non-acid fast bacteria stains blue

25

what species uses acid fast-ziehl neelsen method and why?

mycobacterium sp because of its waxy outer coat

26

how does the fungal stain work

skin scraping --> 10% KOH --> heat gently --> keratin dissolves --> fungi visible

27

do prokaryotes have cell wall

yes except in mycoplasma sp

28

nuclear membrane and nucleolus is present in what?

eukaryotes but def not in prokaryote or viruses

29

difference in ribosomes between prokaryotes, eukaryotes, and viruses

prokaryotes - small 70S (30 and 50)
eukaryotes - large 80S (40 and 60)
virus - absent

30

what type of DNA do plasmids have

circular DNA