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Microbiology > Chapter 6 Microbial Growth > Flashcards

Chapter 6 Microbial Growth Flashcards

(55 cards)

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1
Q

Microbial “Growth”

A
  • increase in population of microbes
  • result of growth is a discrete colony
  • reproduction>growth
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2
Q

Colony

A

aggregation of cells arising from a single parent

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3
Q

Growth Requirements

A
  • nutrients for energy + for building organic molecules
  • common nutrients: c, o, n, h
  • microbes obtain nutrients fr various sources
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4
Q

organisms that require CARBON SOURCE for energy

A

Autotrophs + Heterotrophs

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5
Q

organisms that require energy source

A

Chemotrophs + Phototrophs

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6
Q

Autotrophs

A

require CO2

-food producers, dont need to eat

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7
Q

Heterotrophs

A

require organic compound (carbon-containing compounds)

-must obtain food fr other sources

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8
Q

organisms that require light + CO2

A

Photoautotrophs (plants, algae, cyanobacteria)

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9
Q

organisms that require chem compounds + CO2

A

Chemoautotrophs (uses specific chem compounds like hydrogen, sulfur, + nitrifying bacteria + some archaea)

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10
Q

organisms that require light and organic compound

A

Photoheterotroph (food consumers but can also use light)

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11
Q

organism that require chem compound + organic compound

A

Chemoheterotroph (animals, fungi, protazoa, bacteria, yeast, archaea)

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12
Q

4 types of oxygen requirements for bacteria

A

1 Obligate Aerobes
2 Obligate Anaerobes
3 Facultative Anaerobes
4 Aerotolerant Anaerobes

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13
Q

Obligate Aerobes

A
  • O is essential for life

- aerobic resp ONLY

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14
Q

Obligate Anaerobes

A
  • O is deadly
  • toxic forms of O are highly reactive + excellent oxidizing agents
  • O causes irreparable damage to cells bc missing key enzymes

-fermentation ONLY!

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15
Q

Facultative Anaerobes

A
  • can survive in O
  • will use cellular respiration if O is present,
  • can switch to fermentation if O is NOT present

-both fermentation + aerobic resp

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16
Q

Aerotolerant Anaerobes

A
  • tolerate presence of O bc they have enzymes

- fermenters

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17
Q

aerobes and facultative anaerobes have these enzymes that help tolerate toxic oxygen species

A

superoxide dismutase + catalase

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18
Q

Superoxide Dismutase

A

neutralizes oxygen radicals which are toxic

ex)
O2- > O2
O2 + 2H+ > H2O2

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19
Q

Catalase

A

neutralize peroxide

ex)
H2O2 > 2H2O + O2
peroxide > water and oxygen

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20
Q

4 forms of Toxic Oxygen

A

1 singlet oxygen
2 superoxide radicals
3 peroxide anion
4 hydroxyl radical

-unstable forms of oxygen that has extra electrons that they are trying to get rid of

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21
Q

Catalase Test

A
  • determines if bacteria has enzyme catalase
  • hydrogen peroxide is added to bacteria. if bubble/foams, then positive for catalase
    ex) staph cocci vs strep cocci: staph is catalase pos.
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22
Q

4 Microbe Types based on Temp Requirements

A

[ -5 to 20C] PSYCHROphiles
[ 15 to 45C] MESOphiles
[ 43 to 80C] THERMOPHILES
[67 to 105C] HYPERTHERMOphiles

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23
Q

most pathogenic bacteria based on temp

Study These Flashcards
A

Mesophiles [15 to 45C]

24
Q

pH requirements for microbes

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A
  • organisms are sensitive to changes in acidity

- H+ and OH- interfere with H bonding

25
3 Microbe Types based on pH Requirements
Neutrophiles (most human pathogens) Acidophiles Alkalinophiles
26
Water requirements for microbes
- water is required to dissolve enzymes + nutrients - water is important reactant in many metabolic rxn - when water is not present, bacteria may undergo sporation
27
2 physical effects of water on microbes
1 osmotic pressure | 2 hydrostatic pressure
28
Osmotic Pressure
- pressure exerted on a semipermeable membrane by a soln containing solutes that cannot freely cross - water can freely cross - water will follow salt/ions
29
Hypotonic Soln
lower solute concentration
30
Hypertonic Soln
higher solute concentration
31
Obligate + Facultative Halophiles
organisms that live in high salt concentration
32
Biofilms
- complex relationships among numerous organisms - from slime layer + fimbraea - form on surfaces as a result of quorum sensing - many organisms in a biolfilm are more harmful than a colony of a single type
33
Biofilm Extracellular Matrix
- adhere cells to one another - allows attachment to a substrate - sequester nutrients - may protect individuals in the biofilm
34
Inoculum/Inoculation
introduction of microbes from one place to another medium -for collecting environmental, clinical, and stored specimens
35
Culture
act of cultivation microbes
36
Obtaining Pure cultures
- cultures composed of cells arise from a single progenitor [CFU-colony forming unit] - aseptic technique - isolation technique
37
2 Isolation Techniques
streak plates | pour plates
38
Pour Plate Method
``` -dilution of sample by factors of 10 1mL of initial sample into 9mL of broth 1mL of diluted sample into 9mL of broth repeat and then 1mL of diluted sample into 9mL warm agar ```
39
6 types of Culture Media
``` 1 Selective Media 2 Differential Media 3 Defined Media 4 Complex Media 5 Anaerobic Media 6 Transport Media ```
40
Differential Medium: Blood Agar
-checks for pathogenic form of strepto cocci (Beta-Hemolysis, Alpha-Hemolysis, Gamma-Hemolysis) - beta (positive hemolysis of rbc) - alpha (some clearing, greenish, partial hemolysis, causes pneumonia) - gamma (no hemolysis, no clearings, found in oral cavity)
41
Hemolysis
destruction of red blood cells
42
MacConkey
- selective+differential media - selects for Gram-Neg bacteria - differentiates bw Gram-Neg for Lactose Fermentation
43
MacConkey
- selective+differential media - selects for Gram-Neg bacteria (gram-pos will not grow) - differentiates bw Gram-Neg for Lactose Fermentation (medium turns yellow if positive for fermentation)
44
Preservation of Cultures
- refrigeration (stores for short period of time) - deep-freezing (stores for years) - lyophilization or freeze-drying (decades)
45
Bacterial Growth
- binary fission | - increasing number of bacterial cells
46
Generation Time
time required for bacterial cell to grow and divide - amt of time for 1 cell to grow into 2 cells - dependent on chem + physical conditions - varies among different bacterial species
47
Arithmetical Growth
constant increase. straight line
48
Logarithmic Growth
. grow at an exponential level each time their generation time is up. curved, to steep line
49
Microbial Growth Curve
Lag Phase Log (exponential) Phase Stationary Phase Death (decline) Phase
50
Chemostat
- type of bioreactor - fresh medium is continuously added while culture liquid is continuously removed to keep culture volume constant - can control the growth rate of microbes by changing the rate w which the medium is added
51
Serial Dilution + Viable Plate Count
ways to measure microbial reproduction
52
Metabolic Activity
- distinguishes live and dead cells | - indirect methods of measuring microbial reproduction
53
Lag Phase
bacteria is floral sensing | -in new environment, learning what nutrients + amino acids are available.
54
Log Phase
-number of bacteria grows exponentially until there is no more room to grow.
55
Stationary Phase
maxed out, no more room for growth

Microbiology (26 decks)

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