Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Microbiology > Lecture 3: Cultivation of Bacteria > Flashcards

Lecture 3: Cultivation of Bacteria Flashcards

1
Q

What is bacterial growth and what is it dependent on

A

Population growth/ increase number of cells

Dependent on nutritional factors and other environmental factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some abiotic environmental factors that influence bacterial growth

A

Temperature, pH, oxygen, carbon dioxide, water availability/ osmotic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the minimum, optimum, and maximum temperatures for mesophils

A

Minimum: 10 C
Optimum: 37 C
Maximum: 50 C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the optimal pH for most bacteria

A

6.5-7.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Transport media and cultured media are usually buffered at what pH

A

7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

In terms of oxygen, bacteria are categorized based what two things

A
  1. Requirement for oxygen in metabolic pathways
  2. Ability to counteract ROS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Do obligate aerobes require oxygen and do they have enzymes for ROS

A

Yes to both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Do microaerphile require oxygen and do they have enzymes against ROS

A

Oxygen: yes but at reduced levels and have enzyme to counteract ROS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Do facultative anaerobes require oxygen and do they have enzyme against ROS

A

Don’t require O2 but will use if available, and have enzyme against ROS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Do obligate anaerobes require oxygen and do they have enzyme against ROS

A

No- oxygen is toxic, and don’t have enzyme against ROS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are some examples of special sampling and growth conditions needed for obligate anaerobes

A
  1. Anaerobic transport media
  2. Reducing culture media
  3. Anaerobic jars, bags or chambers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are capnophiles

A

Organisms that require 5-10% CO2 for optimal growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are some ways er can elevate CO2 for capnophiles

A
  1. Candle jar
  2. CO2 packet
  3. CO2 incubator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the purpose of the transport media to prevent desiccation

A

Provide moisture until sample can be cultured

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

T or F: endoscopes resist desiccation

A

True and they contaminate cultures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are halotolerant bacteria

A

Bacteria that don’t require NaCl but can grow under saline conditions (increased osmotic pressure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does it mean for bacteria to be chemohetertrophs

A

Use organic compounds as sources of energy or carbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are fastidious bacteria

A

Bacteria that require additional organic compounds/ vitamins in their culture media

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are some examples of growth factors

A

Vitamins, amino acids, purines, pyrimidines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where are growth factors obtained from

A

Microbes environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

___ Taxa typically require a large number of growth factors

A

Fastidious

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is a liquid media ideal for and what can’t it do

A

Growing large numbers of bacteria

Can’t visually determine number and species present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is a solid media (agars) used for

A

Isolation of pure cultures, estimating the number of viable bacteria

Colony characteristics useful for ID

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a colony

A

Population of cells arising from a single cell, spore or from a group of cells of the same species and strain

25
T or F: agar is a nutrient
False it is a solidifying agent
26
What are semi-solid agars used for
Determining motility, growing microaerophiles, some transport media
27
What type of bacteria can a basal media sustain the growth of
Less fastidious bacteria
28
What are some examples of basal medias
Nutrient agar, nutrient broth, tryptic soy agar
29
What is enriched media and what is it used for
Basal media and additional nutrients (blood, egg yolk) used for fastidious organisms
30
What are some examples of enriched media
Blood agar, chocolate agar
31
What are selective medias
Reagents (dyes, NaCl0 added that inhibit the growth of unwanted bacteria while allow the growth of others
32
What are some examples of selective medias
MacConkey and mannitol salt agar
33
What is MacConkey agar specific for
Gram negative bacteria- bile salts inhibit gram positive
34
What is mannitol salt agar used for
Gram positive
35
What are differential media
Contain components (dyes, ph) that allow the differentiation of closely related taxa based on the appearance (color) of the colony or surrounding media
36
What are some examples of differential media
MacConkey agar, mannitol salt agar, sheep blood agar
37
How is MacConkey agar used as differential media
Bacteria that breakdown lactose will result in a red/pink/purple color ex: E. Coli No lactose but gram negative will be white
38
How is mannitol salt agar used as differential agar
Changes from pink—> yellow Ex: S. Aureus
39
How is sheep blood agar used as differential media
Shows hemolysis
40
What is a transport media used for
Transport of clinical specimens to lab, preserve microbial viability and help maintain the original ratio of microbes in the clinical sample. No nutrients because don’t want microbes to compete with each other and change ratio
41
What is an example of a bacteria that is an obligate intracellular bacteria- grown in animal cells
Rickettsia spp
42
What bacteria is cultivated in armadillos or immunodeficiency mice
Mycobacterium leprae
43
What are the goals of preserving a pure culture
1. Viability 2. Purity 3. Genetic stability
44
How does subculture work to preserve bacterial cells
Transfer cells to fresh medium, incubate, refrigerate and repeat every 2-3 weeks
45
How does snap-freeze cells in broth with cryopreservative preserve bacterial cells
Store in freezers or liquid nitrogen Repeated thawing/freezing reduced viability
46
What is the most common mode of bacterial growth
Binary fission
47
What is generation time
Time required for population to double
48
What is generation time for most bacteria
1-3hrs
49
What is generation time for E. Coli
20 minutes
50
What is generation time for mycobacterium leprae
14 days
51
What is the lag phase in bacterial growth curve
No cell division, cells preparing for growth, duration determined by nutrient types/quanities
52
What is the log phase in bacterial growth curve
Exponential growth, primary metabolites produced
53
What cells in bacterial growth curve are highly vulnerable to antibiotics and detrimental environmental conditions
Log phase cells
54
What is the stationary phase in bacterial growth curve
Zero population growth due to nutrient depletion and waste product toxicity, secondary metabolites produced
55
What is the death/decline phase
Exponential death, some bacteria enter long term stationary phase that can last for years
56
What is a batch culture
Growth in a closed system, exponential growth can’t be maintained
57
What is continuous culture
Growth in a chemostat, fresh medium continuously added, waste continuously removed, exponential growth can be maintained
58
Cells entering stationary/decline phase are where on solid media (agar)
Center
59
Cells entering exponential growth phase are where on solid media/ agar
Edges

Microbiology (31 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions