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Microbiology > Unit 2: Chapter 6 Bacterial Growth, Nutrition, And Differentiation > Flashcards

Unit 2: Chapter 6 Bacterial Growth, Nutrition, And Differentiation Flashcards

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Biology 101 flashcards
1
Q

What are essential nutrients?

A

They are substances bacterial cells require for growth but must acquire from their environment. Many bacteria require only elemental building blocks to produce all chemical compounds required for life.

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2
Q

What are elements that are essential?

A
  1. Carbon
  2. Nitrogen
  3. Phosphorus
  4. Hydrogen
  5. Oxygen
  6. Sulfer
  7. Magnesium
  8. Iron
  9. Potassium
  10. Trace elements (needed in small amounts) such as cobalt, copper, and zinc
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3
Q

What are growth factors?

A

Growth factors are compounds that cannot be made by the organism, so they must be added to the culture media before they will grow

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4
Q

What are carbon compounds?

A
  • they are esential for all forms of life
  • are used as food, which stores energy and is a source of cellular building material for making biomass
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5
Q

Autotrophs

Carbon source for biomass

A

Make their own carbon compounds started with CO2
CO2 is fixed and assembled into organic molecules

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6
Q

Heterotrophs

Carbon source for biomass

A

Obtain carbon compounds from other ogranisms
Acquired from outside the cell

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7
Q

What is light and chemical compounds used as?

A

A source of energy by living things

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8
Q

T or F: Enegry is not an essential need for all forms of life

A

False; Energy is essential for all forms of life

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9
Q

Phototrophs

Energy source

A

Use light as an energy source

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10
Q

Chemotrophs

Energy source

A

Use potential energy stored in chemical compounds as an energy source

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11
Q

Lithotrophs

Electron source

A

Use inorganic chemical compounds

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12
Q

Organotrophs

Electron source

A

Use organic chemical compounds

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13
Q

Which essential nutrient is unavailable for use by most organisms?

A

Nitrogen (N2)

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14
Q

How do you make nitrogen into its usable form?

A

In order for nitrogen to become usable, it has to be “fixed” or converted to ammonium ions (NH4+) which is a form that can be used for biosynthesis.

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15
Q

What is a nitrogen-fixing plant symbiont that forms bacteria-filled nodules on roots?

A

Rhizobium

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16
Q

What is the nitrogen fixation process?

A
  1. Nitrogen is removed from the air and converted to ammonia by nitrogen fixers (rhizobium)
  2. Ammonia is converted to nitrate by nitrifiers (lithotrophs)
  3. Nitrogen is removed from nitrate and converted to nitrogen gas by denitrfiers (aerobic respires)
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17
Q

What precentage of nitrogen is in the air?

A

80%, but it is not useable

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18
Q

Culture Medium

A
  • Nutrients prepared for microbial growth
  • Have to be sterile (not contain living microbes)
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19
Q

Inoculum

A

Microbes introduced into medium

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20
Q

What are the two types of media?

A
  1. Complex media
  2. Chemically defined media
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21
Q

Complex Media

A
  • Does not tell you the exact contents of the media
  • Extracts and digests of yeast, meat, or plants

Eg; Nutrient broth/ Agar

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22
Q

Chemically Defined Media

A

Exact chemical composition is known

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23
Q

Which type of media is used when the bacteria needs special nutrients?

A

Chemically defined media

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24
Q

Agar

A
  • complex polysaccharide
  • used as solidifying agent for culture media in petri plates and slants
  • generally not metabolized by microbes
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25
Q

At what temperature does agar become a liquid?

A

100 degrees C

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26
Q

At what temperature does agar become a solid?

A

~ 40 degrees C

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27
Q

What are the two media types?

A
  1. Selective media
  2. Differential media
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28
Q

Selective media

A

Compounds in the media prevent some type of bacteria from growing, favoring the growth of one specefic type

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29
Q

Differential media

A

Compounds in the media are metabolized differently which allows you to have many different growth types

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30
Q

What is a culture?

A

It is an artifical growth envrionment

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31
Q

What must be provided so that bacteria can grow in a culture?

A

The natural envrionment of the bacteria
Things such as:
1. Nutrition
2. Growth temperature
3. pH
4. Pressure
5. Osmotic Balance
6. O2 and other gasses to serve as electron acceptors

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32
Q

Bacterial growth is measured at the

A

population level

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33
Q

What is growth rate?

A

It is a measyure of the number of cells in a popualtion over time

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34
Q

How do most bacteria reproduce?

A

By binary fission

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35
Q

T or F; binary fission can be symmetrical or
asymmetrical

A

True

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36
Q

How do eukaryotic microbes divide?

A

by mitosis

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37
Q

What is generation time?

A
  • The time required to carry out the whole binary fission process
  • Time can vary
  • It may also tell you how quickly you might develop symptoms depending on immune response
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38
Q

Binary Fission Steps

Just a picture

A
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39
Q

Arithmetic vs. Exponential Plotting

Picture from the powerpoint

A
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40
Q

What is the bacterial growth curve?

A

It shows the change in growth rate over time

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41
Q

Growth Cycle Phases

A
  1. Lag Phase
  2. Log Phase
  3. Stationary Phase
  4. Death Phase
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42
Q

Growth Cycle: Lag Phase

A
  • Bacteria are preparing their cell machinery for growth
  • Cells are not currently growing in this phase
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43
Q

Growth Cycle: Log Phase

A
  • Growth approximates an exponential curve (straight line, on a logarithmic scale)
  • This is the phase where you want to try to kill the bacteria because it is able to absorb everything in this phase
44
Q

Growth Cycle: Stationary Phase

A
  • Cells stop growing and shut down their growth machinery while turning on stress responses to help retain viability
  • The number of cells dividing equals the number of cells dying
  • Develop reistance to antibiotics and host defenses
    1. make endospores
    2. thicken cell walls
    3. form capsules
    4. fight for nutrients
    5. have flagella move them to a more desirable location
45
Q

Growth Cycle: Death phase

A
  • Cells begin to die at an exponential rate
46
Q

T or F; Dying cells can provide nutrients to other cells

A

True

47
Q

Do bacterial cells every completely die off?

A

No, they do not completely die

48
Q

Batch Culture/ Closed System

A

Carries out fermentation with a limited amount of nutrients

49
Q

Continuous Culture/ Open System

A

Continuously carries out fermentation and is constantly providing nutrients, medium, etc

50
Q

In addition to food, bacterial growth considerations include:

A
  1. Temperature
  2. Pressure
  3. Osmotic Balance
  4. pH level

ALL bacteria require these physcial conditions for growth

51
Q

T or F; bacteria all require the SAME physiologic conditons

A

False; “Normal” physiologic condtions vary in differnt types of bacteria

52
Q

Growth vs Tolerance

A
  • Tolerance: Conditions in which the organisms can survive, but CANNOT grow
  • Growth: Conditions that allow for the organsim to growth; end in “-phile”
53
Q

Minimum Growth Temperature

A

The lowest temperature that permits a microbes continued gwoth and metabolism

54
Q

Optimum Growth Temperature

A
  • The temperature that allows the fastest rate of growth and metabolism
  • “-phile”
  • This is where you get max amount of growth
55
Q

Maximum Growth Temperature

A

The maximum temperature at which growth and metabolism can proceed

56
Q

Growth Rate with Temperatures

Just a picture

A
57
Q

Psychrophile

A
  • Most abundent
  • Cold loving
  • Optimal growth at cold temperatures
  • Inhabit snowfields, polar ice, and the deep ocean
  • Dies by ~20C
58
Q

Thermophiles

A
  • Grows best at higher than normal temperatures
  • Live in soil and water associated with volcanic activity, compost piles, and in habittats directly exposed to the sun
  • Survive in thermal springs
59
Q

Hyperthermophiles

A
  • Grows best at extreme temperatures between 80-120C
  • Extreme Thermophiles
  • Survive in thermal springs
60
Q

Mesophiles

A
  • Grows best at moderate temperatures
  • Inhabit animals and plants as well as soil and water in temperate, tropical, and subtropical regions
61
Q

What are most diease causing organisms?

Psychrophile, thermophiles, hyperthermophile, or mesophile?

A

Mesophile

62
Q

Temperature Chart

Just a picture

A
63
Q

What are thermophiles/ hyperthermophiles made of?

A
  • Saturated fatty acids
  • Long carbon chains
  • Solid @ room temperatures
64
Q

What are psychrophiles made of?

A
  • Unsaturated fatty acids
  • Short carbon chains can move easily
  • Liquid @ room temperatures
65
Q

Barometric Pressure

A

Barophiles are able to survive at a very high barometric pressure

66
Q

Water Activity

A

This is how water availability is measured and is approximated by concentration

67
Q

What does interactions with solutes (NaCl) do to water activity?

A

It lowers it

Lowered bc the amount of avaliable water is decreased

68
Q

Osmolarity

A

This is a measure of the number of solute molecules in a solution

69
Q

Hypertonic envrionments cause

A

plasmolysis

Shirnkage of the cell/ dehydration

70
Q

Extreme or Obligate Halophiles

A

require high salt concentrations

Will pump Na out the cell if needed

71
Q

Facultative Halophiles or Halotolerant

A

tolerate high salt concentrations

Will pump Na out the cell if needed

72
Q

How is salt pumped out of the cell?

A

Via active coupled transport
Na+ is pumped out of the cell while K+ (compatable solute) is pumped into the cell

73
Q

How does pH influence the growth of bacteria?

A

It influences the growth by altering the protein shape, which in turn changes protein activity

74
Q

At what pH do MOST bacteria grow in?

A

pH 6.5-7.5

75
Q

At what pH do molds and yeasts grow in?

A

pH 5-6

76
Q

Microbes have adapated to inhabit diverse pH envrionments from

A

0-11.5

77
Q

Acidophiles

A

Organisms that thrive under highly acidc envrionments

pH 0-5

78
Q

Neautralophiles

A

Organisms that thrive under a more neutral envrionment

pH 6-8

79
Q

Alkaliphiles

A

Organisms that thrive under more alkaline (basic) envrionments

pH 9-14

80
Q

pH Chart

Just a picture

A
81
Q

Acidic Condition

A
  • Increase in concentration of H+ ions
  • H+/K+ antiport transport system
  • Pump out H+ and bring in K+
82
Q

Buffering System

dont study this card until verified

A
  • Urease changes urea to NH3 (ammonia)+ CO2
  • Causes body to nutrealize the envrioment
83
Q

How do certian bacteria such as E.coli prevent from becoming too acidic?

A

It can reverse proton influx by importing a variety of cations such as K+ and Na+

84
Q

What does the cell do under extremely alkaline condtions?

A

The cells can use Na+/H+ anti-porters to recruit protons into the cell in exchange for expelling Na+
Na+ out the cell; H+ in the cell

85
Q

How does the reactive oxygen species occur?

A

It occurs when O2 takes on the e- too early in th electron transport chain

86
Q

Which type of organisms are able to destory reactive oxygen species (ROS)?

Aerobes or anaerobes?

A

Aerobes

The terminal electron acceptor of anaerobes are not O2

87
Q

Which enzymes help aid in destroying ROS?

A
  1. superoxide dismutase
  2. peroxidase
  3. catalase
88
Q

What dose superoxide dismutase remove?

A

superoxide

89
Q

What does peroxidase remove?

A

hydrogen peroxide

90
Q

What does catalase remove?

A

hydrogen peroxide

91
Q

Destruction of ROS

Just a picture

A
92
Q

Strict Aerobes

A
  • Appear at the top of the tube
  • Requires oxygen for energy metabolism and survive only in envrionments with oxygen
  • Successfully detoxify reactive oxygen species (ROS)
  • Include ALL groups of life; other than bacteria
93
Q

Strict Anaerobes

A
  • Appear at the very bottom of the tube
  • Does not requires oxygen for energy metabolism and can only survive in envrionments without oxygen
  • May also use fermentation; O2 not final e- acceptor
  • Unable to detoxify ROS which makes oxygen toxic
  • Include BACTERIA ONLY
94
Q

Microaerophiles

A
  • Aerobic, but ROS can be toxic; they make very little enzyme
  • Survive in envrionments with lower oxygen concentration
  • Appear to be in the middle of the tube
95
Q

Aerotolerant Anaerobes

A
  • Appears all over the tube
  • Tolerates O2, but it prefers and is ultimately anerobic
  • Has the ROS system in pace to be able to destory theml; usually lack catalase
96
Q

Facultative Anaerobes

A
  • Appears all over the tube
  • Aerobic AND anaerobic
  • Can survive with or without oxygen
  • Has ROS enzymes
  • Can do both fermentation and aerobic respiration
97
Q

Facultative Aerobes

A
  • Appears mostly at the top of the tube, but can be everywhere
  • Will switch to fermentation if O2 is not present, but prefers O2 envrionment
98
Q

Aerobe vs. Anaerobe in Tube

Just a picture

A
99
Q

What are two ways to culture anaerobes?

A
  1. Anaerobe jar
  2. Anaerobic chamber
100
Q

Anaerobic Jar

A

O2 is removed and CO2 is generated

101
Q

Anaerobic Chamber

A

The glove ports remove the atmosphere via vacuum and replace it with a precise mixture of N2 and CO2 gases.

102
Q

Biofims

A
  • Surface attache communitities
  • Most can grow in these
  • Can be multi or single species
  • Go where it is nutrient rich
  • More resistant to antibiotics
103
Q

Quorum Sensing

A

How cells are able to communicate and coodinate actions

104
Q

Biofilm Formation Steps

A
105
Q

Endospores

A
  • Gram+ bacteria
  • Dormant structure that requires no nutrient or energy
  • Can last a very long time before reactivation may occur

Microbiology (7 decks)

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