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Growth Flashcards

Midterm 2

1
Q

Prokaryotic Cell Divison

A

Binary Fission (semi-conservative)

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2
Q

Generation Time

A

time required by a cell to divide. Cell number doubles per generation and bacteria grow exponentially in ideal conditions

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3
Q

Microbial Growth Curve

A

representation of the number of live cells in a bacterial population over a period of time

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4
Q

Microbial Growth Curve

Lag Phase

A

“flat” period of adjustment for bacterium. Enlargement; little binary fission

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5
Q

Microbial Growth Curve

Exponential Growth Phase

A

a period of maximum division as long as cells have adequate nutrients and a favorable environment
BEST PERIOD FOR A GRAM STAIN

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6
Q

Microbial Growth Curve

Stationary Phase

A

rate of cell growth erquals the rate of cell death, depleted nutrients and gasees, excretion of organic acids and waste products. This about the time when out immune response kicks in
BEST PHASE FOR ENDOSPORE STAIN

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7
Q

Microbial Growth Curve

Death Phase

A

limiting factors intensify, cells die exponentially in their wastes. Log decrease

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8
Q

Methods of Counting Microbes

Methods for TMTC

A

Serial Dilution Method: adding one mL of original culture to 9mL of water/broth to dilute the culture. Continue to do so until you have countable colonies when streaked on plate. 3 plates are streaked and you take the average number of countable colonies

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9
Q

Serial Dilution Method

How to calculate Microbial Count?

A

Microbial Count = Dilution Factor x Number of CFU/mL

ex: Dilution of 1:100,00 yields avg 81 CFU/mL. 81 x 100,000 = 8.1x10^(6)

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10
Q

Methods of Counting Microbes

Methods for low Microbial Numbers

A
  • Concentrate sample via filtration: water passes through but microbes stay on filter
  • Centrifugation: spin to create pellets of cells
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11
Q

Methods of Counting Microbes

Most Probable Number (MPN)

A

a statistical estimate of bacterial numbers using metabolic activity in broth dilutions and comparing the results obtained eith values in an MPN table.

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12
Q

Methods of Counting Microbes

Direct Microscopic Count

any +/-?

A

actual number of cells present in a small representative sample counted on a slide under the microscope

-: can’t tell if cells are dead or alive by this method

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13
Q

Methods of Counting Microbes

Turbidity

any +/-?

A

Approximation by cloudiness. The clodier the sample, the more cells there would be.

-: assumes cloudy=cells when it could be minerals present in sample
+: takes seconds

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14
Q

Methods of Counting Microbes

Electronic Counting

any +/-?

A

Approximation by the number of charged particles

-: assumes charges are from living cells when it could be electrolytes or salts

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15
Q
A
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16
Q

Methods of Counting Microbes

Metabolic Activity

any +/-?

A

Approximation by concentration of metabolic waste products

-: assumes gas is coming from microbes, and that every microbe is metabolizing at same rate. Gas could be result of other reactions within solution

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17
Q

Methods of Counting Microbes

Dry Weight Estimates

any +/-?

A

Approximation by dry cell mass

-: assumes that all cells weigh the same. Moisture can increase weight.

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18
Q

Cardinal Temperatures

A

The range that a particular microbe grows in

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19
Q

Cardinal Temperatures

Minimum Temperature

A

lowest temperature permitting a microbe’s growth and metabolism

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20
Q

Cardinal Temperatures

Maximum Temperature

A

hgihest temperture permitting a microbe’s growth and metabolism

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21
Q

Cardinal Temperatures

Optimum Temperature

A

Best and fastest rate of growth and metabolism

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22
Q

Physical Influence on Growth

Psychrophiles

A

optimum temperature below 15°C, capable of growth at 0°C

about fridge temperature

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23
Q

Physical Influence on Growth

Mesophiles

A

Optimum temperature 20°C-40°C, most human pathogens

room temperature is 2-°C-22°C, Body temperature is 37°C

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24
Q

Physical Influence on Growth

Thermophiles

A

Optimum temperature greater than 45°C

about the temperature of hot water

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25
# Physical Influence on Growth Halophiles
thrive in salty areas of 25-32% NaCl | Salt Lake City, Mono Lake, and beef jerky
26
# Physical Influence on Growth Barophiles
survive in areas under extreme pressure | ocean depths
27
# Physical Influence on Growth Acidophiles
prefer lower pH levels | 1-4.5
28
# Physical Influence on Growth Neutrophiles
prefer neutral-ish pH levels | 5.5-8.5
29
# Physical Influence on Growth Alkalophiles
prefer alkaline conditions/pH levels | 7.5-11.5
30
# Chemical Influence on Growth Aerobes
live and grows in the presence of oxygen | O2 gas makes up 20% of the atmosphere
31
# Chemical Influence on Growth Anaerobes
Microorganism that grows best/exclusively in the absence of oxygen
32
# Chemical Influence on Growth Facultative Anaeobe
Microorganism that doesn't need the presence of oxygen, but can use it if present
33
# Chemical Influence on Growth Aerotolerant anaerobe
microorganisms that don't use oxygen, but can survive and grow in its presence
34
# Chemical Influence on Growth Microaerophile
microorganisms that require a tiny amount of oxygen to grow | about 1-5% of oxygen
35
Reducing Media
media that contains oxygen-removing cheimcals | thioglycolate broths
36
Anaerobic Chambers
special containers absent of oxygen for working with oxygen-sensitive microorganisms
37
Capnophile
bacterium that require high concentrations of carbon dioxide | carbon dioxide makes up 0.04% of the atmosphere
38
How is oxygen toxic?
At high levels, oxygen is very ereactive and generates **Free Radials**, superoxide ions, and hydroxy radicals. The build-up of free radicals destroys membranes, DNA, and cells.
39
How do aerobes and facultative anaerobes detox?
Two pathways: 1. superoxidase dismutase (SOD) 2. Catalase
40
# Detox Pathway Superoxidase Dismutase (SOD) ## Footnote enzyme, substrate, products?
Enzyme: Superoxidase Dismutase (SOD) Substrates: Superoxide, Hydrogen Ion Products: Hydrogen Peroxide and Oxygen
41
# Detox Pathway Catalase ## Footnote enzyme, substrate, products?
Enzyme: Catalse Substrate: Hydrogen Peroxide Products: Water and Oxygen
42
How do obligate anaerobes and aerotolerant anaerobes detox?
Uses Mn++ or peroxidases as an alternative
43
44
# CHONPS Importance of Hydrogen
* Maintains pH * Important for Hydrogen Bonding and polarity * Essential for respiration
45
# CHONPS Importance of Nitrogen
* Is in 80% of the atmosphere * Present in inorganic and organic (aa, DNA, RNA, ATP) nutrients * Microbes are an essential component of the N cycle
46
# CHONPS Importance of Phosphorus
* Found in phosphate which is present in nucleic acids * Essential to genetics, energy transfers (ADP, P(i), ATP)
47
# CHONPS Importance of Sulfur
* Found in sulfides and widely distributed in rocks and sediments * Essential component of some amino acids and vitamines * Stabilizes proteins - disulfide bonds
48
Macronutrients
required in large quantities for cell structure and metabolism ## Footnote Proteins, CHOs, lipids, phosphate, nitrate, etc.
49
Micronutrients
required in tiny amounts for enzyme function and to maintain protein ## Footnote Trace Metals (Manganese, Zinc, Nickel; supplied by TAP WATER in lab) and Organic Growth Factors (May be added to Synthetic Media or Non-synthetic media (Yeast/Blood/Serum/Tissue extracts)
50
Heterotroph
an organism that obtains carbons in an organic form - usually a product of other living/dead organisms | e.g. proteins, CHOs, lipids, and nucleic acids
51
Autotroph
an organism that used carbon dioxide gas or other inorganic forms of carbon as a carbon source | not dependent on other living things
52
Phototroph
an organism that uses light as an energy source
53
Chemotroph
an organism that uses chemicals as an energy source
54
Free-living organism
an organism that isn't dependent on another organism for survival
55
Parasite
one organism benefits at the cost of the other (other is harmed) | (+-)
56
Symbiont
an organism living in symbiosis with another
57
Saprophyte
a plant, fungus, or microorganism that lives on dead or decaying organic matter
58
Commensalist
one organism benefits from another, but the other is unaffected | (+0)
59
Mutualist
both organisms benefit from each other | (++)
60
Antagonist
community members are inhibited or destroyed by others | ex: ABX
61
Synergist
community members cooperate and share nutrients achieving a level of success beyond additive
62
Primary Producer
organisms thaty can produce their own food via photosynthesis or chemosynthesis | sunlight/photosynthesis
63
64
Primary Consumer
plant-eaters, but may also be algae or bacteria eaters | herbivores
65
Secondary consumers
meat-eaters | carnivores
66
Omnivore
organisms that consume both plant and animal
67
5 I's of culturing microbes
1. Inoculation 2. Incubation under correct conditions 3. Isolation into separate colonies 4. Inspection/Information gathering 5. Identification
68
Lab media to grow obligate, intracellular pathogens
These microbes need living hosts to grow and reprodsuce, so embryonated eggs or susceptible animals would be the preferred lab media

microbio (17 decks)

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