Ch. 6 - Microbial Growth

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1

List 3 physical requirements for microbial growth

temperature, pH, osmotic pressure

2

microbes that grow best between 0 - 15 degrees celcius

psychrophiles

3

microbes that grow best between 20 - 30 degrees celcius, refrigerator temperature

psychrotrophs

4

microbes that grow best at high temperatures, 50 - 60 degrees celcius

thermophiles

5

microbes that grow best at moderate temperatures of 25 - 45 degrees celcius

mesophiles

6

optimum temperature for pathogenic bacteria

37 degrees celcius

7

microbes with an optimal growth temperature above 80 degrees celcius

hyperthermophiles

8

microbes that grow in deep ocean or polar areas

psychrophiles

9

microbes that grow in hot springs

thermophiles

10

neutral pH

6.5 - 7.5 pH

11

acidic level of pH

less than 4 pH

12

true or false. Bacteria produced in labs grow acids that interfere with bacterial growth.

True

13

peptones, amino acids and phosphate salts

buffers

14

true or false. Endospores are usually heat resistant

true

15

Percentage of water microorganisms are composed of

80 - 90%

16

effect of high osmotic pressure

removing necessary water from the cell

17

environment where the concentration of a solute is greater than the concentration of water in the cell

hypertonic environment

18

loss of cellular water causing the cell's cytoplasm to shrink

plasmolysis

19

true or false. cell growth is inhibited by plasmolysis because the cytoplasm shrinks and pulls away from the cell wall

true

20

true or false. the addition of salts and increase in osmotic pressure can aid in the preservation of food

true

21

microbes that adapt to high salinity

extreme halophiles

22

microbes that require high salinity for growth

obligate halophiles

23

microbes that do not require high salinity, but are able to grow at salinity of 2%

facultative halophiles

24

complex polysaccharide from marine algae

agar

25

used to solidify microbial growth medium

agar

26

list 5 chemical requirements for microbial growth

carbon, elements: nitrogen, sulfur, & phosphorus, trace elements, oxygen, organic growth factors

27

structural backbone of living matter

carbon

28

microbes that derive carbon from carbon dioxide

chemoautotrophs & photoautotrophs

29

microbes that derive carbon from organic material

chemohertotrophs

30

elements required for protein synthesis

nitrogen & sulfur

31

elements required for DNA and RNA synthesis

nitrogen & phosphorus

32

process of using gaseous nitrogen from the atmosphere

nitrogen fixation

33

element required for synthesis of nucleic acid & phospholipids

phosphorus

34

essential for enzymatic functions

trace elements

35

required by life forms for aerobic respiration

oxygen

36

microbes that require oxygen to live

obligate aerobes

37

bacteria that can continue to grow in the absence of oxygen using fermentation

facultative anaerobes

38

example of a facultative anaerobe

E. Coli

39

microbes unable to use oxygen for energy yielding reactions

obligate anaerobes

40

example of an obligate anaerobe

Clostridium

41

list 2 toxic forms of oxygen

singlet oxygen and superoxide radicals

42

highly reactive oxygen at higher energy levels

singlet oxygen

43

requires superoxide dismutase to neurtralize atmospheric oxygen

superoxide radicals

44

can not use oxygen for growth and ferment carbohydrates to lactic acid

aerotolerant anaerobes

45

microbe used in pickles and cheese

lactobacilli

46

microbes that require oxygen and grow in oxygen concentrations less than air. sensitive to superoxide radicals

microaerophiles

47

organic compounds an organism is unable to synthesize

organic growth factors

48

Three dimensional structure visible using a confocal microscope

biofilm

49

complex polymer in a biofilm

hydrogel

50

cell to cell communication which allows bacteria to coordinate cellular activity

quorum sensing

51

advantageous in facilitating transfer of genetic information

biofilms

52

process where planktonic bacteria attach to a surface and form pillar like structures

biofilm formation

53

essential in sewage treatment

biofilms

54

percentage of human bacterial infections involving biofilms

70%

55

nutrient material prepared for growth of microorganisms in a lab

culture media

56

microbes introduced into a culture medium

innoculum

57

list 6 criteria necessary for a culture to grow in a culture medium

correct nutrients, sufficient moisture, proper pH, sufficient oxygen, sterility, and incubation at proper temperature

58

added to a medium when it is desired to grow a bacteria on a solid medium

agar

59

hard to degrade and liquefies at 100 degrees Celcius

agar

60

Media where the exact chemical composition of a microbe is known

chemically defined media

61

organisms requiring many growth factors

fastidius

62

example of a fastidious organism

lactobacillus

63

used to determine the vitamin concentration in a substance

microbiological assay

64

composed of nutrients including extracts fron yeasts, meats or plants

complex media

65

result of acid reduction in proteins. are digestable by bacteria

peptones

66

liquid form of complex media

nutrient broth

67

media after agar is added

nutrient agar

68

true or false. agar is a nutrient

false

69

uses sodium thioglycolate to combine with dissolved oxygen and deplete oxygen in culture mediu

reducing media

70

list 2 methods used for anaerobic growth

Petri plates and ascorbic acid packets opened and exposed to oxygen

71

Microbes that do not grow on artificial media. Require a living host.

obligate intracellular bacteria

72

used for aerobic bacteria requiring carbon dioxide levels less than or greater than those found in the atmosphere

carbon dioxide incubators

73

true or false. high carbon dioxide levels can be obtained through the use of candle jars

true

74

an example of a microorganism requiring a living host

Mycobacterium leprae

75

microbes that grow at high carbon dioxide concentrations

capnophiles

76

microbe cultured using chemical packets generating carbon dioxide

cyanobacteria

77

suppresses the growth of unwanted bacteria and encourages growth of desired microbes

selective media

78

used to isolate gram negative Salmonella typhi

bismuth sulfite agar; selective media

79

isolates fungi growing at a pH of 5.6

Sabourd's dextrose agar

80

distinguishes colonies of desired organisms from other organisms growing on the sane plate

differential media

81

used to identify bacterial species destroying red blood cells

blood agar

82

example of a blood agar medium that show clear ring around colonies

Streptococcus pyogenes

83

usually a liquid medium used to detect bacteria in small numbers

enrichment culture

84

media used for growth of obligate anaerobes

reducing media

85

media designed to increase the number of microbes to a detectable level

enrichment culture

86

most commonly used isolation method

streak plate method

87

Name the 2 methods for preserving bacterial cultures

deep freezing and lyophilization

88

true or false. Refrigeration can be used for long term storage of cultures

false

89

pure culture suspended in liquid and quickly frozen at =50 to -95 degrees celcius

deep freezing

90

bacterial preservation method where culture can be thawed years after culture has been preserved

deep freezing

91

suspended microbes are quickly frozen at temperatures fro -54 to -72 degrees celcius and undergoes sublimation

lyophlization

92

list 4 methods of bacterial division

binary fission, budding, conidiospore chains, fragmentation

93

most common method of bacterial division

binary fission

94

methods by which filamentous bacteria divide

conidiospore chains and fragmentation

95

the time required for a cell to divide and population double

generation time

96

method of graphing bacterial populations

logarithms

97

list the 4 phases of bacterial growth

lag, log, stationary, death

98

phase of bacterial growth with little or no cell division, but intense metabolic activity

lag phase (beginning phase)

99

phase of bacterial growth where cells actively reproduce and generation time remains constant

log phase

100

phase of bacterial growth where logarithmic plot produces an ascending straight line

log phase

101

phase of bacterial growth where microbial deaths balance to number of new cells

stationary phase

102

phase of bacterial growth where the number of cell deaths exceeds new cells

death phase or logarithmic decline phase

103

list 4 methods of measuring microbial growth

plate count, filtration, most probable number, and direct microscope

104

method of measuring microbial growth where colonies on plates are counted and recorded as colony-forming units

plate count method

105

method of measuring bacterial growth where bacteria is sieved out of a liquid suspension onto a thin membrane

filtration method

106

method of measuring microbial growth where a sample is diluted out in a series of tubes of liquid medium

most probable number method

107

method of measuring microbial growth where a microscope is used to count cell in microscopic field

direct microscope method

108

list 3 indirect methods of measuring microbial growth

turbidity, metabolic activity, and dry weight