Intro Microbiology > Test 3 > Flashcards

Test 3 Flashcards

final test studying type shiiiii (61 cards)

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1
Q

What are the six factors of microbial growth? (POCOLT)

A

pH, oxygen, carbon, osmotic pressure, light, temperature

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2
Q

What are the three classifications of microbes based on pH?

A

Acidophiles, neutrophiles, alkaliphiles

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3
Q

How are microbes classified based on oxygen requirements?

A

Aerobes, Microaerophiles, Anaerobes (obligate, facultative, aerotolerant)

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4
Q

What is an obligate anaerobe?

A

Microbe that cannot tolerate oxygen.

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5
Q

What is a facultative anaerobe?

A

Microbe functions as an aerobe when oxygen is present.

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6
Q

What is an aerotolerant anaerobe?

A

Microbe can still grow in oxygen but does not require it.

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7
Q

What is the difference between a heterotroph and an autotroph?

A

An autotroph uses atmospheric CO2 to grow and heterotrophs use organisms (or sodium bicarbonate in labs)

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8
Q

Describe osmosis.

A

Liquid concentration going from high to low concentration.

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9
Q

Describe the difference between hypertonic and hypotonic in regards to osmosis.

A

Hypertonic: cell has higher concentration inside and undergoes plasmolysis (shriveling)
hypotonic is the migration of liquid from outside to inside cell :D

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10
Q

What type of microbe requires light? what is used to mimic the wavelength of light and why?

A

phototrophs. fluorescent bulbs used in labs because they do not emit heat but provide the required wavelength.

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11
Q

Identify the five classifications of microbes based on temperature requirements. (PPMTT)

A

Psychrophile, psychrotroph, mesophile, thermophile, extreme thermophile.

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12
Q

What is the optimal temperature of psychrophiles and psychrotrophs?

A

0-15C, 20-30C (both can function at 0C tho)

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13
Q

What is the optimal temperature of mesophiles? What makes them special?

A

20-45C. Most microbes are mesophiles as that is our internal temperature.

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14
Q

What are the optimal temperatures of thermophiles and extreme thermophiles?

A

40-80C, 100+C.

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15
Q

Describe the process of preparing a sterile broth tube.

A

autoclave tubes with loose lid, bring it to laminar flow hood (LFH), place broth in flask with water, autoclave the flask with tinfoil over it and take it to the LFH. Pipette the broth into the tubes.

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16
Q

Define a pure culture.

A

A culture containing one strain of a bacteria in solid/liquid media.

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17
Q

What are the types of solid media?

A

LB, TSA; EMB, CNA/Columbia CNA

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18
Q

What makes TSA media unique

A

nutritious as fuck

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19
Q

What does EMB and CNA media select for?

A

EMB selects for gram negative, CNA selects for gram positive.

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20
Q

What does Columbia CNA select for?

A

hemolytic bacteria (using the sheep blood)

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21
Q

List 3 types of enumeration.

A

Direct measurement, viable cell count, turbidimetry

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22
Q

How does direct measurement work?

A

uses microscope to count total cells

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23
Q

Describe the process of viable cell count.

A

serial dilution to count CFUs.

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24
Q

What device does turbidimetry use

A

Spectrophotometer. Indirect count (counts all cells) based on absorbance of fluid in cuvette.

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25
List the phases of cell cultures. (LESD)
Log, exponential, stationary, death
26
How would you store a microorganism for short-term and long-term use?
short: 4C, parafilm in fridge ;) long: freeze dry/"lyophilize"
27
What did Carl Linnaeus suggest
the hierarchy of life (domain, phylum, class, order, family, genus, species)
28
What is Rob Whittaker known for (FAPPM)
kingdom classification system (fungi, animalia, protista, plantae, monera)
29
What is Carl Woebe known for (PEA)
kingdom class system (prokaryotes, eukaryotes, archaea)
30
Define proteobacteria.
Large, gram negative, and most common bacteria
31
List the categories of proteobacteria. (PMNE)
Photosynthetic, methanotrophic, nitrogen-fixing, enteric
32
List some characteristics of photosynthetic proteobacteria.
Facultative anaerobes, purple sulphur/non-sulphur bacteria, perform anoxygenic synthesis via bacteriophyl a/b, located in ponds.
33
List some characteristics of methanotrophic proteobacteria.
Aerobe, works close to methanogens to convert methane to carbon.
34
List some characteristics of nitrogen-fixing proteobacteria.
Anaerobe, found on roots to convert nitrogenous gas into ammonia.
35
List characteristics of enteric proteobacteria.
Gut bacteria, facultative anaerobes, bacillus shape, fermentation via glucose. They have very similar phenotypic traits so tests must be performed to identify based on products.
36
List each test for enteric proteobacteria. (ICUGHsM)
Indole, Citrate, Urease, Gas, Hydrogen Sulfide, Motility
37
Describe how the indole test works.
Tests for indole which is produced when tryptophan is reduced by tryptophanase. If successful, it'll turn red when kovac's reagent is added.
38
Describe how the citrate test works.
Simmon's citrate media used to see if the bacteria can use citrate as an exclusive energy source. it will turn blue if positive.
39
Describe how the urease test works
Urine inoculated onto agar with phenol red as the indicator to see if bacteria makes urease into ammonia. If successful, it'll be pink.
40
Describe how the gas test works
Using a durham tube, phenol red, and a carb (lactose/sucrose), see if microbe forms acid or acid and gas. If gas is present, bubbles will form.
41
Describe how the hydrogen sulfide test works.
Tests to see if microbe can break down sulfur containing the amino acids cysteine/methionine OR reduce sulfur-containing compounds (sulfite, sulfate, thiosulfate). If positive, the produced FeS will cause a black growth.
42
Describe the motility test.
Growth visible from a stab into soft agar. Most bacteria are peritrichous and will pass this test except KLEBSIELLA AND SHIGELLA.
43
What are the roles of your gut microbiome?
Protection, synthesize, digestion, and toxin/carcinogen reduction.
44
What influences your gut microbiome?
Geography, diet, activity, birth conditions (C section), animal presence, and antibiotic usage.
45
List 4 notable 'good' microbes
Lactobacillus, bifidobacteria, rhizobium, yeast
46
What is lactobacillus?
rod-shaped bacteria, lactic acid fermentation.
47
What is bifidobacteria?
Health-promoting bacteria that improves gut barrier
48
What is rhizobium?
Nitrogen-fixing proteobacteria that forms root nodules to convert nitrogen gas into ammonia for the plant.
49
What is yeast?
Eukaryotic microorganism that is goated basically (amazing model organism that can be used in biotech for protein synthesis)
50
List two specific pathogens in relation to food.
Listeria and campylobacter jejuni.
51
What is listeria?
pathogen that can be present in meat or milk.
52
What is campylobacter jejuni?
pathogen that infects meats, more often in birds. When consumed, it is the most common cause of diarrhea.
53
What is biofilm?
Sticky group of bacteria that is literally a film.
54
What is a mechanisms in which bacteria resist antibiotics?
Transposons which are "jumping genes". Causes random gene mutations and altering gene expression.
55
Why has antibiotic resistance become so prevalent?
Misuse due to lack of education (causes excessive use), poor prescription practices (stopping antibiotics too early)
56
What is MRSA?
Any staphylococcal infection that resists the entire penicillin family.
57
What are some future directions for alternatives to antibiotics?
Antimicrobial peptides, antisense technology, quorum sensing, phage therapy
58
What are antimicrobial peptides?
100 or less amino acids in birds or amphibians that disrupt microbial membranes
59
What is quorum sensing?
Interfere with bacteria communication via their molecules
60
What is antisense technology?
synthetic dna that targets reverse-complementary pathogenicity-causing DNA/RNA
61
What is phage therapy?
Use of bacteriophages that are programmed to target specific pathogenic bacteria cells to kill them.
Intro Microbiology
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