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

Exam 2 (Ch. 6 Microbial Growth) Flashcards

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Biology 101 flashcards
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
Q

name 4 organic compounds

A

carbs, proteins, lipids, nucleic acids

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26
Q

4 chemical requirements for growth

A

nitrogen, phosphorus, sulfur, trace elements

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27
Q

nitrogen (3 things)

A
  1. 2nd most abundant element
  2. used to make proteins and nucleic acids
  3. found in nature as ammonia, N2 gas, or nitrate
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28
Q

phosphorus

A

used to make DNA, RNA, ATP, and phospholipids

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29
Q

sulfur

A

used to make vitamins and amino acids

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30
Q

trace elements (def. and ex.)

A

needed in small amounts for enzymes to function, ex: Fe, Cu, Zn, Mg

31
Q

aerobe (def.)

A

uses oxygen

32
Q

anaerobe (def.)

A

doesn’t use oxygen

33
Q

obligate aerobe (def. and ex.)

A

must have oxygen, ex: Micrococcus luteus

34
Q

obligate anaerobe (def. and ex.)

A

dies in the presence of oxygen, ex: Clostridium tetani

35
Q

facultative anaerobe (def. and ex.)

A

uses oxygen when present but can grow without it,

ex: E. coli

36
Q

aerotolerant anaerobe (def. and ex.)

A

can survive in presence of oxygen but grows better without it, ex: Lactobacillus

37
Q

cardinal temperatures (def.)

A

min., opt., and max. temperatures

38
Q

minimum temperature (def.)

A

lowest temperature at which growth will occur

39
Q

optimum temperature (def.)

A

temp at which growth is most rapid

40
Q

maximum temperature (def.)

A

highest temp. at which growth will occur

41
Q

psychrophile (5 things)

A
  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
Q

psychrotroph (2 things)

A
  1. optimum 20-30 degrees C

2. ex: Staphlococcus aureus (food spoiler)

43
Q

mesophile (5 things)

A
  1. moderate temp. loving
  2. 25-40 degrees C
  3. most common
  4. found in animals, soil and water
  5. ex: E. coli
44
Q

thermophile (4 things)

A
  1. heat loving
  2. opt. 50-60 degrees C
  3. found in volcanoes, hydrothermal vents and hot springs
  4. ex: Thermus aquaticus
45
Q

acidophile (3 things)

A
  1. opt. pH below 6.5
  2. found in areas with sulfuric or hydrochloric acid (hot springs)
  3. ex: fungi, Helicobacter pylori, Lactobacillus
46
Q

Helicobacter pylori

A

likes to live in your stomach and can cause ulcers

47
Q

alkaliphiles (3 things)

A
  1. opt. pH above 8
  2. found in soda lakes
  3. ex: Bacillus alkalophilus
48
Q

neutrophiles (2 things)

A
  1. opt. pH 7

2. most bacteria are in this category

49
Q

halophiles (3 things)

A
  1. require high salt concentration
  2. found in Dead Sea or Great Salt Lake
  3. ex: Halococcus
50
Q

growth requirements for most microbes (3 things)

A
  1. mesophiles
  2. pH (neutral) 7
  3. little salt
51
Q

plate count (2 things)

A
  1. most common method

2. measures number of viable cells

52
Q

serial dilution (explain)

A

bacteria are added to tubes at varying dilutions, poured into plates, allowed to grow

53
Q

a plate with the highest dilution will have the _______ amount of bacteria (growth)

A

least

54
Q

pour plate method (5 things)

A
  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
Q

spread plate method (3 things)

A
  1. bacteria added to solid agar
  2. spread over surface of agar with sterile rod
  3. colonies only on surface of agar
56
Q

direct microscopic count (def.)

A

look through a microscope and count the number of bacteria

57
Q

Pros of direct microscopic count

A

no incubation time (fast) and cheap

58
Q

Cons of direct microscopic count

A

dead cells are counted

59
Q

2 types of plate counts

A

pour plate and spread plate

60
Q

4 types of measurement for microbial growth

A
  1. plate count
  2. direct microscopic count
  3. turbidity
  4. most probable number
61
Q

MPN stands for

A

most probable number

62
Q

turbidity (4 things)

A
  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
Q

most probable number (MPN) (5 things)

A
  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
Q

generation

A

1 cell dividing into 2

65
Q

generation time

A

time it takes for the population size to double

66
Q

growth curve (3 things)

A
  1. graph that plots growth of a population
  2. used to calculate generation time
  3. uses logarithmic scale
67
Q

4 phases of growth, in order

A

lag phase, log or exponential phase, stationary phase, death phase

68
Q

lag phase (2 things)

A
  1. period of adjustment

2. slow growth

69
Q

log or exponential phase

A

population is doubling

70
Q

stationary phase (2 things)

A
  1. equal number of cells dividing and dying

2. due to depletion of nutrients, accumulation of waste, drop in pH

71
Q

death phase

A

cells are dying

72
Q

2 ways of preserving bacterial cultures

A

flash-freezing and lyophilization

73
Q

flash-freezing

A

pure culture of bacteria are quickly frozen at -50 to -95 degrees Celsius

74
Q

lyophilization (4 things)

A
  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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