Cultivation, Reproduction And Growth Of Bacteria Flashcards

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1
Q

Growth of bacteria is represented by

A

Increase in number of cells rather than size

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2
Q

Requirements for growth

A

Nutritional and physical

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3
Q

Nutritional Requirements for growth

A
Energy and carbon source
Nitrogen
Sulfur
Phosphorus
Potassium magnesium and calcium
Trace elements
Organic growth factors 
Water
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4
Q

Phototrophs and chemotrophs

A

Use solar energy as source of energy

Oxidize chemical compounds for energy

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5
Q

All organisms require a ____ source as it is the structural basis of biochemicals

A

Carbon

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6
Q

Heterotrophs and autotrophs

A

Use an organic carbon source

Use CO2 as a carbon source

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7
Q

Four nutritional classes of microorganisms

A

Chemoautotrophs (chemolithoautotrophs)

Chemoheterotrophs

Photoautotrophs

Phtoheterotrophs

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8
Q

Nitrogen is needed for_____

Obtained:

A

Protein and nucleic acid synthesis

Obtained via decomposition of proteins or from NH4+ or NO3-

Some bacteria can fix nitrogen

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9
Q

Sulfa is needed to

Sources

A

Synthesize sulfur contained amino acids and vitamins (thiamine and biotin)

Sources: sulfate ions, hydrogen sulfide, amino acids

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10
Q

Phosphorous is needed

Source

A

For synthesis of nucleic acids, phospholipids and ATP

Phosphate ions

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11
Q

Potassium, Magnesium and calcium function as

A

Cofactors for enzymes

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12
Q

Trace elements

A

Required in small amounts and essential for enzyme activity and act as cofactors usually.

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13
Q

Organic Growth Factors (definition)

A

Organic compounds essential for the growth of bacterium that cannot be manufactured by the bacterium; must be obtained from the environment

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14
Q

Organic growth factors

A

Vitamins - (coenzymes) either manufactured or obtained via environment

Amino Acids - needed for protein synthesis

Purines and pyrimidines - needed for nuclei acid synthesis

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15
Q

Water

A

Nutrients must be in solution with water to be used

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16
Q

Physical conditions required for growth

A

Temperature
Gaseous atmosphere
pH (Acidity or alkalinity)
Other (osmotic pressure, salinity, light, hydrostatic pressure)

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17
Q

Temperature as a condition for growth

A

Affects growth, reaction rates and amount of growth. Most bacteria grow within a limited range of temperature

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18
Q

Classification of organisms based on temperature

A

Psychorphiles
Mesophiles
Thermophiles

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19
Q

Psychrophiles

A

Cold loving

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20
Q

Mesophiles

A

Moderate temperature loving microbes

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21
Q

Thermophiles

A

Heat loving

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22
Q

Optimum growth temperature

A

Temp in which organism grows most rapidly

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23
Q

Psychotrophs

A

(Insert

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24
Q

Hyperthermophiles

A

Insert

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25
Q

Obligate aerobes

A

Use molecular oxygen and produce more energy from nutrients than do microbes that do not use oxygen

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26
Q

Facultative anaerobes

A

Use molecular oxygen when present but are able to use fermentation or anaerobic respiration when free oxygen is not available

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27
Q

Obligate Anaerobes

A

Cannot use molecular oxygen for energy yielding reactions

28
Q

Aerotolerant anaerobes

A

Cannot use oxygen for growth, but tolerate it

29
Q

Microaerophiles

A

Grow only in oxygen concentrations lower than air

30
Q

What must AEROBES, FACULTIVE ANAEROBES & AEROTOLREANT ANAEROBES have to neutralize superoxide free radicals formed in the presence of atmospheric oxygen?

A

Enzyme: superoxide dismutase and either catalase or peroxidase

31
Q

Superoxide dismutase converts free radical into

(02-)+(O2-) +(2H+) —–>

A

Molecular oxygen and hydrogen peroxide

H2O2 + O2

32
Q

Since peroxide anions are toxic (O2-), an organism must use…. and convert hydrogen peroxide into ….

A

Catalase —- water and oxygen

33
Q

Since peroxide anions are toxic (O2-), an organism could also use…. and convert hydrogen peroxide into ….

A

Peroxidase to covert it to water

34
Q

Most bacteria grow best in a narrow range of pH near

But the exception is

A

PH 5-8

Yeasts and molds which have a greater range

35
Q

Buffers are used to….

examples include….

A

Prevent a shift in pH of the environment.

Peptones, amino acids, phosphate salts

36
Q

Osmotic pressure is required as a _______ for microbes

A

Solvent for nutrients

37
Q

Most bacteria grow in ranges between ____ & _____ (salinity)

A

0.85% (physiological saline) and 3.5% (seawater);

38
Q

________ require high salt environments at a range of ___ to ____

A

Obligate halophiles

18-24%

39
Q

_______ bacteria that do NOT require high salt environments but can grow in concentrations up to _____%

A

Facultative halophiles (2%)

40
Q

Light is required for

A

Photosynthetic organisms

41
Q

Hydrostatic pressure is

A

Pressure applied to liquid.

42
Q

Most microorganisms can tolerate _____ pressure

A

Hydrostatic

43
Q

Type of organism that grows BETTER or ONLY at pressures greater than one atmosphere

A

Facultative Barophiles or Obligate Barophiles

44
Q

Facultative

A

Better

45
Q

Obligate

A

Only

46
Q

Natural medium

A

Medium made of things found in nature i.e. Potato starch

47
Q

Prepared medium

A

Measured ingredients, distilled water, adjusted pH, and dispensment after sterilization in autoclave

48
Q

Chemical defined (synthetic) media

A

Prepared from pure chemicals of known concentrations

49
Q

Chemically complex medium

A

Prepared from extracts of natural materials

50
Q

Blood vs chocolate agar

A

Cooled to 50 vs 80 degrees Celsius

Hemoglobin turns brown in chocolate

51
Q

Anaerobic growth reducing media

A

Chemically removes molecular oxygen that could interfere with growth of Anaerobes

Ex. Thioglyocolate

52
Q

Reducing media in a Petri dish - method

A

Incubation in anaerobic jar or chamber

53
Q

Selective media

A

Minimal essential media in which specific chemicals are added that will inhibit growth of one microbe and allow others to grow

54
Q

Differential media

A

Minimal essential media with specific indicator chemicals that will produce a pattern of growth or color change in the media or organism allowing distinction of one org from another

55
Q

Enrichment media

A

Minimal essential media to which nutrients have been added that will support the growth of fastidious heterotrophs

56
Q

Special culturing technique for fastidious bacteria

A

Culture in living animal or cell

57
Q

Generation time

A

Time required for cell to divide. Dependent on species and environment

58
Q

Bacterial growth curve

A

Representation of growth of microbe in medium in phases

59
Q

Lag phase

A

No appreciable increase in number of cells but cell materials are being manufactured for division.

60
Q

Log Phase

A

Exponential growth. Cell population is doubling at rapid pace. PHASE in which Microbial agents are tested.

61
Q

Plateau phase or stationary phase

A

Number of cells living and dividing is equal to the number dying
Nutrient depletion begins

62
Q

Decline Phase

A

Number of cells dying exceed the number dividing

63
Q

Cause of decline Phase

A

Nutrient depletion and production of toxins and waste

64
Q

If inoculating an organism into a non familiar nutrient base, what impact will it have on the lag phase?

A

It will delay it or prolong because bacteria have to activate certain enzymes to metabolize the nutrient base

65
Q

ADVERSE conditions during plateau and decline could begin formation of

A

Endospores

66
Q

Measurement of Microbial growth

A
Plate counts
Filtration
Most probable number
Direct microscopic count
Estimation: optical density,metabolic activity, dry weight (Fungi)