1.2 Bacterial Growth and Nutrition Flashcards

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1
Q

Decomposition of nitrogen-containing compounds

A

Nitrogen fixation

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1
Q

Process of Bacterial Cultivation (7)

A
  1. Isolation and identification of organisms 2. Determination of antibiotic assay 3. Antibiotic and vitamin assays 4. Biological testing of products destined for human use 5. Food and water analysis 6. Industrial testing 7. Environmental control
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1
Q

MEASUREMENT OF POPULATION GROWTH

A
  1. CELL NUMBER/CELL COUNT 2. CELL MASS
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2
Q

Physical Requirements of Microbes

A
  1. Temperature 2. Atmosphere 3. Hydrogen ion concentration (pH) 4. Osmotic pressure 5. Hydrostatic pressure
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2
Q

the most rapid cell growth occurs at what part of the culture?

A

Edge

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2
Q

type of cell mass determination used in fungi

A

Direct

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3
Q

Log phase continues until one of two things happens

A
  1. nutrients in the medium become exhausted 2. toxic metabolic products accumulate and inhibit growth
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3
Q

is defined as the time (t) per generation

A

Generation time

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4
Q

organisms that thrive at >80°C (70°C to 110°C)

A

HYPERTHERMOPHILES

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5
Q

Useful in public health microbiology especially in determining water quality

A

SELECTIVE/DIFFERENTIAL MEDIA

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6
Q

Operates best at high dilution rates and Culture medium lacks a limiting nutrient

A

Turbidostats

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7
Q

Example is: fungi best grows on bread, dry rot of wood, survival of bacterial endospores

A

XEROPHILES/XEROTOLERANT

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7
Q

Used to identify lactose-fermenting gram negative bacteria like E. coli

A

MacConkey Agar/DIFFERENTIAL MEDIA

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8
Q

Phase when cells may be growing in volume or mass, synthesizing enzymes, proteins, RNA; only increase in metabolic activity

A

Lag Phase

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9
Q

lack superoxide dismutase and catalase

A

ANAEROBES

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10
Q

electron acceptor in aerobic respiration

A

Oxygen

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12
Q

14% of phospholipid layer of cell membrane (dry weight)

A

Nitrogen

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12
Q

at the most favourable temperatures for growth, the number of cell divisions per hour (growth rate) generally doubles for every increase of __°C

A

10°C

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13
Q

Most stable and effective at lower dilution rates

A

Chemostats

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15
Q

serves as cofactor for enzymes, complexes with ATP and stabilizes ribosomes and cell membranes

A

Magnesium

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15
Q

Chemically undefined, prepared from natural products

A

Complex Media

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15
Q

Examples are Petroff-Hauser, hemocytometer, Coulter counter

A

Direct Cell Counting

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16
Q

do not require oxygen for growth → may use it for energy yielding chemical reactions

A

FACULTATIVE AEROBES

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17
Q

optimal T for pathogenic organisms

A

37°C

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17
Q

The microbial mixture is transferred to the edge of an agar plate with an inoculating loop or swab and then streaked out over the surface in one of several patterns.

A

STREAK PLATE

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19
Q

use of atmospheric or gaseous N for cell synthesis

A

Nitrogen fixation

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21
Q

CLASSES OF GROWTH FACTORS

A

Amino acids Purines/Pyrimidines Vitamins

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23
Q

What are the Macroelements?

A

Carbon Nitrogen Hydrogen Oxygen Sulfur Phosphorus

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23
Q

organisms that thrive at 40 – 85°C

A

THERMOPHILES

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24
Q

Contain substrates which inhibit the growth of one group of bacteria while allowing the growth of another

A

SELECTIVE MEDIA

25
Q

20% of phospholipid layer of cell membrane (dry weight)

A

Oxygen

26
Q

maintain pH, forms H bonds in macromolecules, and act as prime force in oxidation

A

Hydrogen

26
Q

pressure-dependent microbes, die in low hydrostatic pressure environment because of gas vesicles that expand upon decompression and cells rupture

A

Barophiles

28
Q

e.g. Marine bacteria; Vibrio parahemolyticus

A

HALOPHILES/HALOTOLERANT

29
Q

Allows the separation of different groups of bacteria based on variations in colony size or color using dyes as pH indicators

A

DIFFERENTIAL MEDIA

30
Q

process of becoming a dormant cell that resists adverse condition

A

Sporulation

32
Q

make up all or part of enzyme co-factors and only very small amounts sustain growth

A

Vitamins

33
Q

contributes to heat resistance and bacterial endospores

A

Calcium

34
Q

Nutrient medium with extra growth factors, such as blood; No inhibitory agent is used to prevent the growth of unwanted organisms

A

ENRICHMENT MEDIA

35
Q

TYPES OF MEDIA ACCORDING TO COMPOSITION where Exact composition is known

A

Chemically defined or Synthetic

36
Q

cannot withstand a 21% level of oxygen; grow best at oxygen levels between 1 and 15%

A

MICROAEROPHILIC

38
Q

most important chemical requirement, next to water

A

Carbon

38
Q

The protective mechanisms of aerobes that allow them to survive with ambient Oxygen

A

superoxide dismutase

39
Q

Macroelements are required in (amount)

A

Grams/Liter

40
Q

50% of phospholipid layer of cell membrane (dry weight)

A

Carbon

42
Q

force with which water moves through the cytoplasmic membrane from a solution containing a low concentration of dissolved substances (solutes) to one containing a high solute concentration

A

OSMOTIC PRESSURE

43
Q

organisms that thrive at 15 – 20°C

A

PSYCHROTROPHS

45
Q

at refrigerator temperature (4-10°C) they spoil food stored for prolonged periods

A

PSYCHROTROPHS

46
Q

Present in ug/L

A

Trace elements

48
Q

Original sample is diluted several times to reduce the microbial population sufficiently to obtain separate colonies upon plating

A

POUR PLATE

49
Q

Contains neutral red dye, which becomes pink in the presence of acids produced by the fermentation of lactose.

A

MacConkey Agar/DIFFERENTIAL MEDIA

50
Q

4 Phases of Growth Curve

A

Lag Log/Exponential Stationary Decline

52
Q

With superoxide dismutase but without catalase

A

AEROTOLERANT

54
Q

Nutrients are used for what 2 purposes?

A
  1. Biosynthesis 2. Energy Production
55
Q

Major element in all organic compounds

A

Hydrogen

56
Q

A population of cells arising from a single cell, to characterize an individual species.

A

Pure culture

56
Q

to ensure continued growth where culture volume and the cell concentration are both kept constant by adding fresh medium at the same rate that used cell-containing medium is removed

A

CONTINUOUS CULTURES: OPEN SYSTEM

57
Q

pressure exerted on cells by the weight of the water resting on top of them

A

HYDROSTATIC PRESSURE

58
Q

Blood Agar Plate is for gram ____ organisms

A

Positive

60
Q

usually poisoned by oxygen

A

ANAEROBES

61
Q

measurement of growth inhibition caused by the antibiotics

A

MICROBIOLOGICAL ASSAY

62
Q

the ideal solidifying agent

A

Agar

63
Q

Hydrogen composition in cell membranes

A

8% of phospholipid layer of cell membrane (dry weight)

64
Q

used to determine the precise nutritional requirements (media)

A

Chemically defined or Synthetic

65
Q

main form of Phosphorus

A

Phosphate

66
Q

Dilute microbial mixture is transferred to the center of an agar plate and spread evenly over the surface with a sterile bent glass rod

A

SPREAD PLATE

67
Q

can stand hypertonic environments whether salt, sugar, or other dissolved solutes

A

OSMOPHILES

68
Q

Meant to simulate and improve on the natural environment

A

Complex Media

69
Q

organisms that thrive at 25 – 40°C

A

MESOPHILES

70
Q

organisms that thrive at 0 – 15°C

A

PSYCHROPHILES

71
Q

can grow in a standard air atmosphere of 21% oxygen

A

Aerobes

72
Q

Trace elements

A

Zn, Cu, Mn, Mo, Co, Ni

73
Q

microorganisms that require some NaCl for growth

A

HALOPHILES/HALOTOLERANT

74
Q

organic compounds required because they are essential cell components or precursors of such component and cannot be synthesized by the organism

A

Growth Factors