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microbio > Growth > Flashcards

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
Q

Physical Influence on Growth

Halophiles

A

thrive in salty areas of 25-32% NaCl

Salt Lake City, Mono Lake, and beef jerky

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26
Q

Physical Influence on Growth

Barophiles

A

survive in areas under extreme pressure

ocean depths

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27
Q

Physical Influence on Growth

Acidophiles

A

prefer lower pH levels

1-4.5

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28
Q

Physical Influence on Growth

Neutrophiles

A

prefer neutral-ish pH levels

5.5-8.5

29
Q

Physical Influence on Growth

Alkalophiles

A

prefer alkaline conditions/pH levels

7.5-11.5

30
Q

Chemical Influence on Growth

Aerobes

A

live and grows in the presence of oxygen

O2 gas makes up 20% of the atmosphere

31
Q

Chemical Influence on Growth

Anaerobes

A

Microorganism that grows best/exclusively in the absence of oxygen

32
Q

Chemical Influence on Growth

Facultative Anaeobe

A

Microorganism that doesn’t need the presence of oxygen, but can use it if present

33
Q

Chemical Influence on Growth

Aerotolerant anaerobe

A

microorganisms that don’t use oxygen, but can survive and grow in its presence

34
Q

Chemical Influence on Growth

Microaerophile

A

microorganisms that require a tiny amount of oxygen to grow

about 1-5% of oxygen

35
Q

Reducing Media

A

media that contains oxygen-removing cheimcals

thioglycolate broths

36
Q

Anaerobic Chambers

A

special containers absent of oxygen for working with oxygen-sensitive microorganisms

37
Q

Capnophile

A

bacterium that require high concentrations of carbon dioxide

carbon dioxide makes up 0.04% of the atmosphere

38
Q

How is oxygen toxic?

A

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
Q

How do aerobes and facultative anaerobes detox?

A

Two pathways:
1. superoxidase dismutase (SOD)
2. Catalase

40
Q

Detox Pathway

Superoxidase Dismutase (SOD)

enzyme, substrate, products?

A

Enzyme: Superoxidase Dismutase (SOD)
Substrates: Superoxide, Hydrogen Ion
Products: Hydrogen Peroxide and Oxygen

41
Q

Detox Pathway

Catalase

enzyme, substrate, products?

A

Enzyme: Catalse
Substrate: Hydrogen Peroxide
Products: Water and Oxygen

42
Q

How do obligate anaerobes and aerotolerant anaerobes detox?

A

Uses Mn++ or peroxidases as an alternative

43
Q
A
44
Q

CHONPS

Importance of Hydrogen

A
  • Maintains pH
  • Important for Hydrogen Bonding and polarity
  • Essential for respiration
45
Q

CHONPS

Importance of Nitrogen

A
  • 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
Q

CHONPS

Importance of Phosphorus

A
  • Found in phosphate which is present in nucleic acids
  • Essential to genetics, energy transfers (ADP, P(i), ATP)
47
Q

CHONPS

Importance of Sulfur

A
  • Found in sulfides and widely distributed in rocks and sediments
  • Essential component of some amino acids and vitamines
  • Stabilizes proteins - disulfide bonds
48
Q

Macronutrients

A

required in large quantities for cell structure and metabolism

Proteins, CHOs, lipids, phosphate, nitrate, etc.

49
Q

Micronutrients

A

required in tiny amounts for enzyme function and to maintain protein

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
Q

Heterotroph

A

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
Q

Autotroph

A

an organism that used carbon dioxide gas or other inorganic forms of carbon as a carbon source

not dependent on other living things

52
Q

Phototroph

A

an organism that uses light as an energy source

53
Q

Chemotroph

A

an organism that uses chemicals as an energy source

54
Q

Free-living organism

A

an organism that isn’t dependent on another organism for survival

55
Q

Parasite

A

one organism benefits at the cost of the other (other is harmed)

(+-)

56
Q

Symbiont

A

an organism living in symbiosis with another

57
Q

Saprophyte

A

a plant, fungus, or microorganism that lives on dead or decaying organic matter

58
Q

Commensalist

A

one organism benefits from another, but the other is unaffected

(+0)

59
Q

Mutualist

A

both organisms benefit from each other

(++)

60
Q

Antagonist

A

community members are inhibited or destroyed by others

ex: ABX

61
Q

Synergist

A

community members cooperate and share nutrients achieving a level of success beyond additive

62
Q

Primary Producer

A

organisms thaty can produce their own food via photosynthesis or chemosynthesis

sunlight/photosynthesis

63
Q
A
64
Q

Primary Consumer

A

plant-eaters, but may also be algae or bacteria eaters

herbivores

65
Q

Secondary consumers

A

meat-eaters

carnivores

66
Q

Omnivore

A

organisms that consume both plant and animal

67
Q

5 I’s of culturing microbes

A
  1. Inoculation
  2. Incubation under correct conditions
  3. Isolation into separate colonies
  4. Inspection/Information gathering
  5. Identification
68
Q

Lab media to grow obligate, intracellular pathogens

A

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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