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Bacteriology > Lecture 3 - Cultivation of Bacteria > Flashcards

Lecture 3 - Cultivation of Bacteria Flashcards

1
Q

What are the five major environmental factors that affect bacterial growth?

A 
Temperature 
pH 
Oxygen 
Carbon Dioxide 
Water avalibility / Osmotic pressure
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2
Q

What are obligate growth factors?

A

These growth factors are restricted aka these conditions are a must for the bacteria to grow

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3
Q

What are Facultative growth factors?

A

These growth conditions have a little more give to them when it comes to conditions the bacteria will grow in

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4
Q

What most pathogenic bacteria when it comes to temperature?

A

Mesophiles

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5
Q

What conditions are optimal for mesophiles?

A

37 degrees C

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6
Q

What is special about 37 degrees C?

A

Body temp

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7
Q

What is the pH that is optimal for most bacteria?

A

6.5 to 7.5

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8
Q

What are most pathogenic bacteria when it comes to pH?

A

Neutrophiles

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9
Q

What are transport + culture media buffered at most of the time?

A

pH of 7.0

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10
Q

What are two factors that are taken into consideration when deciding if a bacteria can handle oxygen or not?

A

Do they grow in oxygen or not
– and –
Can they handle ROS

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11
Q

Describe obligate aerobes?

A

Oxygen require + ROS enzymes present

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12
Q

Describe microaerophiles.

A

Oxygen required at low levels + ROS enzymes present

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13
Q

Describe facultative anaerobes.

A

Oxygen not require but will growth if present + ROS enzymes present

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14
Q

Describe aerotolerant anaerobe.

A

No preference for oxygen + Some ROS enzymes

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15
Q

Describe obligate anaerobes.

A

Oxygen kills + NO ROZ enzymes

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16
Q

What methods are used to grow obligate anaerobes?

A

Anaerobic transport media
Reducing media
Anaerobic jars/bags/chambers

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17
Q

What are capnophiles?

A

Require 5 to 10% CO2 for optimal growth

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18
Q

What kind of bacteria tend to be capnophiles?

A

Microaerophiles

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19
Q

What methods are used to increase CO2 levels?

A

Candle jar
CO2 packet
CO2 incubator

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20
Q

What are halotolerant bacteria?

A

Bacteria do not need NaCl but can grow in higher concentrations

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21
Q

What does increased NaCl cause?

A

Increased osmotic pressure

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22
Q

What are halophiles?

A

Grow best under saline conditions

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23
Q

In regards to bacterial nutrition, what are most bacteria?

A

Chemoheterotrophs

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24
Q

What are chemoheterotrophs?

A

Bacteria that need organic compounds for energy and carbon

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25
Q

What are fastidious bacteria?

A

Tend to need additional organic compounds on their media

26
Q

What are growth factors?

A

Vitamins + AA’s + Purines + Pyrimidines

27
Q

Why are growth factors important?

A

Essential for growth because the bacteria is not able to synthesis these compounds themselves.

28
Q

What are three common states of bacteriological media?

A

Liquid + Solid + Semi-Solid

29
Q

What are liquid medias good for?

A

Growing large numbers of bacteria

30
Q

What is the down side to using liquid media?

A

Cannot see if the sample has been contaminated and contains more than one species

31
Q

What is a colony?

A

Population of cells arising from single cell or spore or from a group of cells that are from the same species/strain

32
Q

What is the benefit of using solid media?

A

Good for pure cultures and estimating the number of viable bacteria

33
Q

What is the reason for using semi-solid agars?

A

Determining motility
Growing microaerophiles
Transport media

34
Q

What is important to remember about agar within a media?

A

It is a solidifying agent NOT A NUTRIENT

35
Q

What are the two categories of chemical composition in regards to media?

A

Chemically defined + Complex media

36
Q

What is chemically defined media?

A

Exact chemical composition is known

Made from pure reagents

37
Q

What is the purpose of using chemically defined media?

A

Exact growth requirements for bacteria known

Experimental purpose

38
Q

What are complex medias?

A

Some components are not known

39
Q

What would be a reason to use a complex media?

A

Routine culture of most bacteria

40
Q

What is a basal media?

A

Sustains growth of less fastidious bacteria

41
Q

What are examples of basal media?

A

Nutrient agar or broth

42
Q

What is an enriched media?

A

Basal media + more nutrients

Cultures of fastidious organisms

43
Q

What are examples of enriched medias?

A

Blood agar + Chocolate agar

44
Q

What are selective medias?

A

Reagents are added to inhibit the growth of unwanted bacteria but allowing growth of bacteria of interest

45
Q

What are examples of selective media?

A

MacConkey + Mannitol Salt

46
Q

What is differential media?

A

Components are put in media that allow differentiation of closely related taxa based on appearance of media OR colonies

47
Q

What are examples of differential media?

A

MacConkey + Mannitol Salt + Sheep Blood Agar

48
Q

What are the three goals to preservation of bacteria?

A

Viability
Purity
Genetic stability

49
Q

What are three ways to preserve bacteria?

A

Subculture of growing cells
Snap-freeze
Freeze-dry

50
Q

What does subculturing growing cells entail?

A

Transfer cells to fresh medium, incubate, refridgerate, repeat

51
Q

What is the downside to subculturing bacteria?

A

Contamination
Labor intensive
Mutations can occur

52
Q

What is the down side to snap freezing?

A

Viability can be affected

53
Q

Besides binary fission, what are three other examples of bacterial growth?

A

Budding + Fragmentation + Conidiospores

54
Q

What is generation time?

A

Time for population to double

55
Q

What is a normal generation time for bacteria?

A

1 to 3 hours

56
Q

What are the four phases of bacterial growth?

A

Lag - Log - Stationary - Death

57
Q

What is happening during the lag phase of the bacterial growth curve?

A

Bacteria is not growing but rather preparing to undergo division
Duration determined by environmental factors

58
Q

What is occurring during the log phase of bacterial growth?

A

Primary metabolites are being created

Cells are growing at a rapid rate

59
Q

What is important to clinically known about the log phase of bacterial growth?

A

At this time bacteria is most susceptible to antibiotics and harsh environmental conditions

60
Q

What is occurring during the stationary phase of bacterial growth curve?

A

Zero population growth
Growth = Death
Secondary metabolites produced

61
Q

What is the most common method which bacteria use to replicate?

A

Binary fission

Bacteriology (28 decks)

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