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Microbiology > Chapter 6 > Flashcards

Chapter 6 Flashcards

Microbial Growth (66 cards)

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1
Q

The term for the sum of all chemical reactions within a living organism?

A

Metabolism

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2
Q

What is the main end product of Glycolysis?

A

ATP

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3
Q

Define or explain the 3 primary groups of microorganism on the basis of their preferred general range of temperature in celsius

A

Psychrophiles -7 –19 C
Mosophiles 10–48 C
Thermophiles 40–72 C

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4
Q

An organism that uses oxygen when present but can grow without oxygen is called

A

Faculatrive Anarobes

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5
Q

An organism that require oxygen concentration lower than air to grow is called

A

Microaerophiles

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6
Q

Whal is th ebiosafetly level (BSL) for most introductory microbiology laboratory?

A

BSL-1 for intro

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7
Q

This type of culture media contain inhibitors to suppress unwanted microbes and encourage desired microbes

A

Selective Media

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8
Q

This type of planting method is used isolate pure cultures

A

Streak Plate Method

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9
Q

List in order the 4 phases of the bacterial growth curve

A

LAG Phase
LOG Phase
Stationary Phase
Death

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10
Q

Define “Generation Time”

A

time required for a cell to divide and can be from 2 min to 1 day
E.Coli takes about 20 min and this is after preparing for 40 min prior to that 20 min

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11
Q

Name at least 2 methods for direct measurements of microbial growth

A

Plate count
Direct microscopic count

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11
Q

What are the physical requirements for Growth?

A

Temperature
pH
Osmotic pressure

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12
Q

The requirements for Growth Chemical requirements?

A

Carbon
Nitrogen, sulfur, and phosphorous
Trace elements
Oxygen
Organic growth factors

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12
Q

Psychrophiles

A

cold-loving
cause food spoliage

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13
Q

Mesophiles

A

Moderate-temerature-loving

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14
Q

Thermophiles

A

Heat-loving
Optimum growth temperature
Found in hot springs and organic compost

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14
Q

Hyperthermophiles

A

Optimum growth temperature above 80C

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15
Q

Molds and Yeasts grow between the pH of

A

5-6

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16
Q

Osmotic Pressure

A

Want to explode/implode
Hypertonic environments (higher in solutes than inside the cell) cause
plasmolysis due to high pressure

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17
Q

Chemical Requirements of
Carbon

A

structural backbone of organic molecules
Chemoheterotrophs use organic molecules as energy
Autotrophs use CO2

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18
Q

Chemical Requirements
Nitrogen

A

component of proteins, DNA, and ATP
bacteria decompose protein material
from organic material
A few bacteria use N2 in nitrogen fixation
Critical need bacteria so plants can suck up in roots

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19
Q

Chemical Requirements of
Sulfur

A

Used in Amino acids, thiamine and biotin

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20
Q

Chemical Requirements of
Phosphorus

A

used in DNA RNA and ATP
in cell membranes

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21
Q

Trace elements that are required in small amounts usually as enzyme cofactors

A

Iron, copper, molybdenum, and zinc

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22
Obligate aerobes
Require oxygen Growth occurs only where high concentrations of O2 have diffused into the medium
23
Facultative anaerobes
grow via fermentation or anaerobic respiration when oxygen is not available Growth is best where most oxygen is present, but occurs throughout tube.
24
Anaerobes
Unable to use oxygen and most are harmed by it
25
Aerotolerant anaerobes
tolerate but cannot use oxygen Growth occurs evenly oxygen has no effect well diffused
26
Microaerophiles
require oxygen concentration lower than air Needs O2 but small amount Growth occurs only where a low concentration of oxygen has diffused into medium
27
Obligate Anaerobes
growth ceases in presence of O2 Growth occurs only where there is no O2
28
Biofilms
Form slime or hydrogels that adhere to surfaces Bleach will not kill them involved in 70% of infections Cell-to-cell via quorum sensing (aware of neighbors) Bacteria secrete inducer signialying chemically to bacterial cells (Dome)
29
Sterile
no living microbes
30
Inoculum
introduction of microbes into a medium
31
Cultrue
microbes growing in or on a culture medium
32
culture medium
nutrients prepared for microbial growth
33
Agar
Complex polysaccharide used as solidifying agent for culture media (petri plates) Liquefies at 100 C Boiling point Solidifies at 40 C
34
Reducing media
get rid of Oxygen due to cultivation of anaerobic bacteria No O2 present
34
Chemically defined media
exact chemical composition is known require certain type of chemical
35
Complex media
extracts and digests of yeastys meat, or plants; chemical composition varies batch to batch and are different things that the bacteria likes Nutrient broth 86 jello consistency Nutrient Agar Broth that contains jellos
36
Capnophiles
require high Co2 conditions Candle jar-Burn giving CO2
37
Chemically defined
Growth of chemoautotrophs and photoautotrophs; microbiological assays
37
Differential Media
Allow distinguishing of colonies of how different microbes on the same plate changing colors How to distinguish between species
38
Selective Media
Suppress unwanted microbes and encourage desired microbes contain inhibitors to suppress growth of all others & loves particular amound while inhibiting others Gram + happy and inhibits for Gram - Growth like salt
39
Complex
Growth of most chemoheterotrophic organisms
40
Reducing
Growth of bligate anaerobes
41
Selective
Suppression of unwanted microbes; encouraging desired microbes
41
Differential
Differentiation of colonies of desired microbes from others
42
colony
is a population of cells arises from a single cell or spore to from a group of attached cells
43
Streak plate method
is used to isolate pure culutres counting bacterias
44
Preserving bacterial cultures
Deep-freezing: -50 to -95C Lyophilization (freeze drying) frozen -54 to -72 and then dehydrated in a vacuum Water is harmful to cell expands when its frozen such out water to preserve Cryofreezing
45
Generation time
Time required for a cell to divide
46
Binary Fission in Bacteria
1 cell elongates and DNA is replicated 2 cell wall and plasma membrane begin to constrict 3 cross-wall forms, completely separating the two DNA copies 4 Cells seperate
47
Cell division generation number
doubles every time
47
Stationary phase
Bacteria approach the carrying capactity
48
Direct Measurement of Microbial Growth
count microbial cells Plate count Filtration Most probable number method Direct microscopic count
49
Which of the following do you consider to be a countable plate?
25-3000
50
Pour plate method
inoculate empty plate add melted nutrient agar swirl to mix colonies grow on and in solidified medium
50
Serial dilution
streak plate to ensure the right number of colonies, the original inoculum must be diluted 1:10 1:100 1:1000 1:10000 1:100000 taking 10 ml from original
51
The spread plate method
inoculate plate containing solid medium spread inoculum over surface evenly colonies grow only on the surface of medium
52
Filtration
solution passed through a filter that collects bacteria which is then transferred to a petri dish and grows as colonies on the surface
53
MPN Most Probable Number Method
Multiple tube test Count positive tubes Compare with a statistical table (pain to do it inoculates water)
54
Direct microscopic count
petroff-Hausser cell counter # of bacteria.mL = # of cells counted/volume of area counted
55
Indirect methods of estimating bacterial numbers
Turbidity Metabolic activity Dry weight
56
Turbidity
measurement of cloudiness wiht a sprectrophotometer
57
Metabolic ativity
amount of metabolic product is proportional to the number of bacteria
58
Dry weight
bacteria are filtered, dried, and weighed used for filamentous organisms (hairy hard to count)

Microbiology (4 decks)

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