Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Microbiology > Chp 6 > Flashcards

Chp 6 Flashcards

(79 cards)

Start Studying
1
Q

The Requirements for Growth for microbials

A

1) Physical requirements
- Temperature
- pH
- Osmotic pressure

2) Chemical requirements
- Carbon
- Nitrogen, sulfur, and phosphorous
- Trace elements
- Oxygen
- Organic growth factors

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

Physical requirements for microbial growth… Temp

A

1) Minimum growth temperature
2) Optimum growth temperature
3) Maximum growth temperature

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

Physical requirements for microbial growth… Temp

1) cold loving
2) moderate temp loving
3) heat loving

A

1) Psychrophiles—cold-loving
2) Mesophiles—moderate-temperature-loving
3) Thermophiles—heat-loving

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

Psychrotrophs

Grow between what temps

A

0C and 20 to 30C

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

Psychrotrophs cause

A

Cause food spoilage

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

Thermophiles

Optimum growth temperature of

A

50 to 60C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Thermophiles are found

A

Found in hot springs and organic compost

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

Hyperthermophiles Optimum growth temperature

A

> 80*C

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

Most bacteria grow between pH

A

6.5-7.5

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

Molds and yeasts grow between pH

A

5-6

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

Acidophiles grow in what environments

A

acidic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Facultative halophiles tolerate

A

tolerate high osmotic pressure

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

Hypertonic environments (higher in solutes than inside the cell) cause

A

plasmolysis due to high osmotic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Extreme or obligate halophiles require

A

high osmotic pressure (high salt)

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

Carbon

A
  • Structural backbone of organic molecules
  • Chemoheterotrophs use organic molecules as energy
  • Autotrophs use CO2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Nitrogen is a component of

A

proteins, DNA, and ATP

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

A few bacteria use N2 in

A

nitrogen fixation

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

Most bacteria decompose protein material for the

A

nitrogen source

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

Sulfur

A
  • Used in amino acids, thiamine, and biotin
  • Most bacteria decompose protein for the sulfur source
  • Some bacteria use SO42– or H2S
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Phosphorus

used in

A

DNA, RNA, and ATP

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

Phosphorus found in

A

membranes

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

PO43– is a source of

A

phosphorus

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

Most bacteria decompose protein for the

A

sulfur source

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

Trace Elements

A
  • Inorganic elements required in small amounts
  • Usually as enzyme cofactors
  • Include iron, copper, molybdenum, and zinc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Obligate aerobes and oxygen
requires oxygen
26
Facultative anaerobic and oxygen
grow via fermentation or anaerobic respiration when oxygen is not available
27
Obligate anaerobes and oxygen
oxygen and are harmed by it
28
Aerotolerant anaerobes and oxygen
tolerate but cannot use oxygen
29
Microaerophiles and oxygen
require oxygen concentration lower than air
30
Singlet oxygen:
(1O2−) boosted to a higher-energy state and is reactive
31
Organic compounds
- obtained from the environment | - Vitamins, amino acids, purines, and pyrimidines
32
biofilms
1) Microbial communities 2) Form slime or hydrogels that adhere to surfaces 3) Bacteria communicate cell-to-cell via quorum sensing 4) Share nutrients 5) Shelter bacteria from harmful environmental factors
33
Biofilms Found in
digestive system and sewage treatment systems; can clog pipes
34
Biofilms 1000x resistant to
microbicides
35
Biofilms are involved in what percentage of infections
70% Catheters, heart valves, contact lenses, dental caries
36
Culture medium
nutrients prepared for microbial growth
37
sterile means
no living microbes
38
Inoculum:
introduction of microbes into a medium
39
Culture
microbes growing in or on a culture medium
40
Culture medium Agar is a
1) Complex polysaccharide 2) Liquefies at 100C Solidifies at ~40C
41
Used as a solidifying agent for culture media in Petri plates, slants, and deeps
Agar
42
Agar is Generally not metabolized by
microbes
43
Chemically defined media:
exact chemical composition is known
44
Fastidious organisms are those
that require many growth factors provided in chemically defined media
45
Complex media:
extracts and digests of yeasts, meat, or plants; chemical composition varies batch to batch
46
Nutrient broth and Nutrient agar are both examples of
complex media: extracts and digests of yeasts, meat, or plants; chemical composition varies batch to batch
47
Reducing media is used for
the cultivation of anaerobic bacteria
48
Reducing media contains
Contain chemicals (sodium thioglycolate) that combine O2 to deplete it
49
Reducing media is heated to
drive off O2
50
Capnophiles
-Microbes that require high CO2 conditions - CO2 packet - Candle jar
51
Biosafety levels
- BSL-1: no special precautions; basic teaching labs - BSL-2: lab coat, gloves, eye protection - BSL-3: biosafety cabinets to prevent airborne transmission - BSL-4: sealed, negative pressure; "hot zone" - Exhaust air is filtered twice through HEPA filters
52
Selective media
- Suppress unwanted microbes and encourage desired microbes | - Contain inhibitors to suppress growth
53
Differential media allow
Allow distinguishing of colonies of different microbes on the same plate
54
Some media have both
selective and differential characteristics
55
Enrichment Culture encourages
the growth of a desired microbe by increasing very small numbers of a desired organism to detectable levels
56
enrichment culture is usually a solid or liquid?
liquid
57
A pure culture contains
only one species or strain
58
A colony is a
population of cells arising from a single cell or spore or from a group of attached cells
59
A colony is often called a
colony-forming unit (CFU)
60
The streak plate method is used to
isolate pure cultures
61
Preserving Bacterial Cultures
Deep-freezing: –50 to –95C Lyophilization (freeze-drying): frozen (–54 to –72C) and dehydrated in a vacuum
62
Bacterial Division
1) Increase in number of cells, not cell size 2) Binary fission 3) Budding 4) Conidiospores (actinomycetes) 5) Fragmentation of filaments
63
Generation Time
is time required for a cell to divide | 20 mins- 24 hrs
64
Binary fission
doubles the number of cells each generation
65
In generation time | Total number of cells =
2 number of generations
66
In generation time Growth curves are represented
logarithmically
67
Phases of Bacterial Growth
1) Lag phase 2) Log phase 3) Stationary phase 4) Death phase
68
Direct measurements–count microbial cells
1) Plate count 2) Filtration 3) Most probable number (MPN) method 4) Direct microscopic count
69
Plate Counts, count
colonies on plates that have 30 to 300 colonies (CFUs)
70
To ensure the right number of colonies during plate counts, the original inoculum must be diluted via
serial dilution
71
Counts are performed on bacteria mixed into a
with agar (pour plate method) or spread on the surface of a plate (spread plate method)
72
Filtration
- Solution passed through a filter that collects bacteria | - Filter is transferred to a Petri dish and grows as colonies on the surface
73
The Most Probable Number (MPN) Method
- Multiple tube test - Count positive tubes - Compare with a statistical table
74
Direct Microscopic Count
1) Volume of a bacterial suspension placed on a slide 2) Average number of bacteria per viewing field is calculated 3) Uses a special Petroff-Hausser cell counter
75
Direct Microscopic Counts equation
Number of bacteria/ml= number of cells divided by volume of area counted
76
Turbidity
measurement of cloudiness with a spectrophotometer
77
Metabolic activity
amount of metabolic product is proportional to the number of bacteria
78
Dry weight
bacteria are filtered, dried, and weighed; used for filamentous organisms
79
estimating bacterial numbers by indirect methods
Turbidity Metabolic Activity Dry Weight

Microbiology (9 decks)

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