Lecture 5 Microbial Growth And Physiology Flashcards

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1
Q

Boiling is what temperature and how long

A

•100 degrees celcius
•30 minutes

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2
Q

Autoclave is at what temperature and for how long

A

120 degrees celcius
30 minutes

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3
Q

Dry heat is at what temperature and for how long

A

•150 degrees celcius
•120 minutes

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4
Q

What process do bacteria divide by

A

Binary fission

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5
Q

When the chromosome divides during binary fission what does it produce

A

Two identical copies

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6
Q

Is Bacterial growth described as exponential

A

Yes the generation time (time for bacterial mass to double) can be as fast as 20 minutes

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7
Q

What temperature does agar melt as

A

100 degrees celcius

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8
Q

What temperature does agar solidify at

A

40 degrees celcius

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9
Q

How is Agar sterilised

A

By Autoclaving

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10
Q

What do bacteria grow as on agar

A

As Colonies

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11
Q

How many cells/ml for growth in a liquid medium

A

10^9 cells/ml

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12
Q

For growth in a liquid medium what is position for incubation

A

Standing or Agitated

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13
Q

What are the growth phases of a Bacterial Culture

A

•Lag
•Log
•Stationary
•Death

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14
Q

Describe each of the growth phases of a Bacterial Culture

A

•Lag
Adaption
•Log
Cells multiply at the maximum rate
•Stationary
Lack of nutrients and build up of toxic metabolic intermediates means multiplication is balanced by cell death
•Death

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15
Q

Describe the two direct measurements of Bacterial growth

A

•Total Cell Count
Using microscope and counting chamber

•Total Viable Count
Cells in culture are diluted and spread on nutrient agar plates

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16
Q

Total viable count is a serial ___ -fold dilution

A

10

17
Q

Name the indirect measurement of bacterial growth

A

•Turbidity
•Cloudiness
•Measure live and dead cells

18
Q

What is the nm of a filter or prism in a Spectrophotometer

A

•540nm

19
Q

In a Chemostat culture what is cell density controlled by

A

Nutrient Concentration

20
Q

What is Growth rate controlled by in a Chemostat culture

A

By the flow rate of nutrient

21
Q

What does Growth require

A

•Energy
•Building blocks required for construction of cellular machinery
•Appropriate environmental conditions

22
Q

Name the nutrient requirements for Growth

A

– Water
– Carbon (carbohydrate)
– Nitrogen (protein)
– Inorganic salts Iron - siderophores – Oxidation of organic compounds
– (carbohydrates, lipids, proteins)

23
Q

What temperature is required for Growth

A

20-110 degrees celcius

24
Q

What pH is required for Growth

A

4.0-9.0

25
Q

What type of Atmosphere for growth

A

O2/ No O2

26
Q

What is Energy derived from

A

The enzymatic breakdown of organic substrates (carbohydrates,lipids or proteins) in a process called CATOBOLISM

27
Q

What is Energy generated from CATABOLISM used to synthesise

A

Cellular constituents in a process called ANABOLISM

28
Q

Catabolism + Anabolism =

A

Metabolism

29
Q

Other than carbohydrates,lipids and proteins where else can bacteria derive energy from

A

•Plastic
•Rubber
•Toxic compounds like Phenol

30
Q

What are Auxotrophs

A

The ability of individual bacterial species to produce their own cellular components will dictate its nutritional requirement

31
Q

Obligate Aerobes grow only in the presence of what

A

O2

32
Q

Obligate Anaerobes grown only in the absence and are killed by

A

O2

33
Q

Facultative Anaerobes grow in the presence and absence and of

A

O2

34
Q

What are Psychrophile bacteria

A

•Cold loving bacteria
•10-20 degrees Celsius

35
Q

What are Mesophile bacteria

A

•Human body temperature
•Pathogens
•Opportunists
•20-40 degrees Celsius

36
Q

What are Thermophile Bacteria

A

•Heat loving
•>60 degrees Celsius

37
Q

Some bacteria can grow / survive in what ph

A

•acid
•alkali