Principles of Micro 2

Question 1

describe the experiment by Louis Pasteur

Answer 1

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

Question 2

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

Answer 2

it became contaminated once exposed to the air

Question 3

describe the work of Robert Koch

Answer 3

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

Question 4

what are Koch’s postulates

Answer 4

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

Question 5

what were problems with Koch’s postualtes

Answer 5

• 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

Question 6

who is John Snow

Answer 6

• father of epidemiology

- showed contaminated pump handles were contaminating water causing cholera

Question 7

who is Edward Jenner

Answer 7

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

Question 8

what is Ignaz Semmelweiss known for

Answer 8

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

Question 9

describe the work of Anthon von Leeuwenhoek

Answer 9

he came up with the early microscope

Question 10

what is magnification, resolution, and resolving power

Answer 10

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

Question 11

factors the limit microscopic magnification of microorganisms

Answer 11

resolution, resolving power, wavelength

Question 12

light source and max magnification for brightfield

Answer 12

visible

1500x

Question 13

light source and max magnification for fluorescence

Answer 13

UV

1500x

Question 14

light source and max magnification for TEM

Answer 14

electrons

500,000 - 1,000,000 x

Question 15

light source and max magnification for SEM

Answer 15

electrons

10,000 - 1,000,000x

Question 16

what are two different ways to prep specimen for microscopic viewing

Answer 16

• placing live specimen on surface then putting a coverslip
• kill specimen then put coverslip

for both preparation one can put dye or stain

Question 17

when will one use a live vs. killed specimen

Answer 17

live: motility, cell behavior, short term
killed: physical appearance, longer term storage

Question 18

what does the positive stain stick to

Answer 18

• the actual specimen providing color

- basic (neg aspect)

Question 19

what does the negative stain stick to

Answer 19

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

Question 20

what color does the gram positive and gram negative stain

Answer 20

gram + - purple

gram neg - pink

Question 21

when does one gram stains

Answer 21

for some bacterias but it can’t stain all

Question 22

what is Paul Ehrlich known for?

Answer 22

the stain method called acid fast - ziehl neelsen method

Question 23

how does the acid fast-ziehl neelsen method work

Answer 23

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

Question 24

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

Answer 24

the acid-fast bacteria stains pink/red

while the non-acid fast bacteria stains blue

Question 25

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

Answer 25

mycobacterium sp because of its waxy outer coat

Question 26

how does the fungal stain work

Answer 26

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

Question 27

do prokaryotes have cell wall

Answer 27

yes except in mycoplasma sp

Question 28

nuclear membrane and nucleolus is present in what?

Answer 28

eukaryotes but def not in prokaryote or viruses

Question 29

difference in ribosomes between prokaryotes, eukaryotes, and viruses

Answer 29

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

Question 30

what type of DNA do plasmids have

Answer 30

circular DNA

Question 31

how does bacteria genome differ from fungi and viruses

Answer 31

• they are mainly circular with the exception of one
• smaller in size
• single chromosome with no associated proteins

Question 32

what separates the surface structures from the internal structures in bacteria?

Answer 32

cell wall – also keeps cells rigid

Question 33

importance of capsule

Answer 33

helps to temporarily escape phagocytosis

prevent bacteriophage attachment

Question 34

importance of fimbriae/common pili

Answer 34

help attach to surfaces or tissue

help bacteria attach to each other for urinary system

Question 35

importance of flagellae

Answer 35

for motility

Question 36

different between gram positive and gram negative surface structure

Answer 36

gram positive - cytoplasmic membrane and peptidoglycan

gram negative - cytoplasmic membrane, peptidoglycan, and outer membrane

Question 37

difference in peptidoglycan between gram positive and gram negative

Answer 37

gram negative has a thinner peptidoglycan layer

Question 38

what does gram positive have that gram negative does not

Answer 38

techoic acid and lipotechoic acid

Question 39

importance of cell wall in bacteria when it comes to antibiotic treatment

Answer 39

cell wall of bacteria is made up of peptidoglycan only found in bacteria so can be used as a unique target for antibiotics

Question 40

other than antibiotic factor, what is the importance of cell wall in bacteria

Answer 40

contributes to symptoms of disease
defines cell shape
maintains osmotic integrity