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Microbiology > Exam 2 (Ch. 6 Microbial Growth) > Flashcards

Exam 2 (Ch. 6 Microbial Growth) Flashcards

(74 cards)

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1
Q

Growth (def.)

A

increase in number of cells

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2
Q

colonies

A

groups of cells that can be seen without a microscope

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3
Q

what does CFU stand for

A

colony forming units

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4
Q

another name for colony forming units is

A

colony

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5
Q

things needed for growing microbes (4 things)

A
  1. chemical needs for microbe must be determined-media (what do they eat)
  2. media is made and sterilized (autoclaved)
  3. microbe is inoculated into media
  4. inoculated media is placed in proper env’t (temp, pH, oxygen, light, etc.)
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6
Q

autoclave (def.)

A

heat under pressure for 20 min.

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7
Q

culture (def.)

A

microbe growing on the media

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8
Q

inoculate (def.)

A

process of adding/ introducing microbes to the media

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9
Q

incubate (def.)

A

the appropriate time and temp to grow the specific bacteria

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10
Q

enrichment culture (def.)

A

set of conditions such as temp, pH, salinity, light, nutrients, and oxygen that are tailored to requirements of desired microbe

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11
Q

pure culture (def.)

A

one type of microbe

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12
Q

mixed culture (def.)

A

2 or more types of microbes

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13
Q

how many zones are created to isolate pure colonies

A

four

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14
Q

zone one has the fewest _____ colonies and zone four has the most

A

isolated

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15
Q

zone four has the most______colonies

A

isolated

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16
Q

culture media (def.)

A

nutrient material made for the growth of microbes (food)

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17
Q

nutrient broth (def.)

A

liquid media

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18
Q

agar (def.) (3 things)

A
  1. solidifying agent
  2. liquid at 100 degrees C
  3. solid at 40 degrees C
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19
Q

complex media (def. and ex.)

A

media that uses substances where precise contents are unknown. ex: yeast extract, casein, beef extract, etc.)

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20
Q

chemically defined media (def.)

A

exat chemical composition is known

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21
Q

selective media (def. and ex.)

A

designed to encourage only growth of desired microbe,

ex: sabouraud agar pH of 5.6 to grow fungi

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22
Q

differential media (def. and ex.)

A

contains substances that allow different microbes to be identified growing on the same media, ex: S. aureus growing on MSA turns the agar from red to yellow when present

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23
Q

MSA tands for

A

mannitol salt agar

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24
Q

carbon (2 things)

A
  1. most abundant element

2. used to make carbs, proteins, lipids, and nucleic acids

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25
name 4 organic compounds
carbs, proteins, lipids, nucleic acids
26
4 chemical requirements for growth
nitrogen, phosphorus, sulfur, trace elements
27
nitrogen (3 things)
1. 2nd most abundant element 2. used to make proteins and nucleic acids 3. found in nature as ammonia, N2 gas, or nitrate
28
phosphorus
used to make DNA, RNA, ATP, and phospholipids
29
sulfur
used to make vitamins and amino acids
30
trace elements (def. and ex.)
needed in small amounts for enzymes to function, ex: Fe, Cu, Zn, Mg
31
aerobe (def.)
uses oxygen
32
anaerobe (def.)
doesn't use oxygen
33
obligate aerobe (def. and ex.)
must have oxygen, ex: Micrococcus luteus
34
obligate anaerobe (def. and ex.)
dies in the presence of oxygen, ex: Clostridium tetani
35
facultative anaerobe (def. and ex.)
uses oxygen when present but can grow without it, | ex: E. coli
36
aerotolerant anaerobe (def. and ex.)
can survive in presence of oxygen but grows better without it, ex: Lactobacillus
37
cardinal temperatures (def.)
min., opt., and max. temperatures
38
minimum temperature (def.)
lowest temperature at which growth will occur
39
optimum temperature (def.)
temp at which growth is most rapid
40
maximum temperature (def.)
highest temp. at which growth will occur
41
psychrophile (5 things)
1. cold-loving 2. can grow at 0 degrees C 3. opt. below 5-15 degrees C 4. found in glaciers and deep in ocean 5. ex: Polaromonas vacuolata
42
psychrotroph (2 things)
1. optimum 20-30 degrees C | 2. ex: Staphlococcus aureus (food spoiler)
43
mesophile (5 things)
1. moderate temp. loving 2. 25-40 degrees C 3. most common 4. found in animals, soil and water 5. ex: E. coli
44
thermophile (4 things)
1. heat loving 2. opt. 50-60 degrees C 3. found in volcanoes, hydrothermal vents and hot springs 4. ex: Thermus aquaticus
45
acidophile (3 things)
1. opt. pH below 6.5 2. found in areas with sulfuric or hydrochloric acid (hot springs) 3. ex: fungi, Helicobacter pylori, Lactobacillus
46
Helicobacter pylori
likes to live in your stomach and can cause ulcers
47
alkaliphiles (3 things)
1. opt. pH above 8 2. found in soda lakes 3. ex: Bacillus alkalophilus
48
neutrophiles (2 things)
1. opt. pH 7 | 2. most bacteria are in this category
49
halophiles (3 things)
1. require high salt concentration 2. found in Dead Sea or Great Salt Lake 3. ex: Halococcus
50
growth requirements for most microbes (3 things)
1. mesophiles 2. pH (neutral) 7 3. little salt
51
plate count (2 things)
1. most common method | 2. measures number of viable cells
52
serial dilution (explain)
bacteria are added to tubes at varying dilutions, poured into plates, allowed to grow
53
a plate with the highest dilution will have the _______ amount of bacteria (growth)
least
54
pour plate method (5 things)
1. bacteria added to liquid agar 2. mixture poured into empty plates 3. agar solidifies, plate incubated 4. colonies grow within and on surface of agar 5. plates with 30-300 colonies are used to calculate original cell concentration
55
spread plate method (3 things)
1. bacteria added to solid agar 2. spread over surface of agar with sterile rod 3. colonies only on surface of agar
56
direct microscopic count (def.)
look through a microscope and count the number of bacteria
57
Pros of direct microscopic count
no incubation time (fast) and cheap
58
Cons of direct microscopic count
dead cells are counted
59
2 types of plate counts
pour plate and spread plate
60
4 types of measurement for microbial growth
1. plate count 2. direct microscopic count 3. turbidity 4. most probable number
61
MPN stands for
most probable number
62
turbidity (4 things)
1. more bacteria in liquid culture means more turbid (cloudy) 2. beam of light passes through the test tube 3. more bacteria, less light will pass through 4. uses spectrophotometer
63
most probable number (MPN) (5 things)
1. used when plate counts aren't reliable 2. estimates number of microbes in original sample using a serial dilution 3. positive results seen by gas production 4. a table estimates the number of microbes in original sample 5. used in testing water purity
64
generation
1 cell dividing into 2
65
generation time
time it takes for the population size to double
66
growth curve (3 things)
1. graph that plots growth of a population 2. used to calculate generation time 3. uses logarithmic scale
67
4 phases of growth, in order
lag phase, log or exponential phase, stationary phase, death phase
68
lag phase (2 things)
1. period of adjustment | 2. slow growth
69
log or exponential phase
population is doubling
70
stationary phase (2 things)
1. equal number of cells dividing and dying | 2. due to depletion of nutrients, accumulation of waste, drop in pH
71
death phase
cells are dying
72
2 ways of preserving bacterial cultures
flash-freezing and lyophilization
73
flash-freezing
pure culture of bacteria are quickly frozen at -50 to -95 degrees Celsius
74
lyophilization (4 things)
1. pure culture is flash frozen 2. vacuum is used to remove water 3. result is powder residue 4. bacteria revived by adding liquid media

Microbiology (12 decks)

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