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Microbiology > Chapter 6 > Flashcards

Chapter 6 Flashcards

Microbial Growth

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Biology 101 flashcards
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
Q

Obligate aerobes

A

Require oxygen

Growth occurs only where high concentrations of O2 have diffused into the medium

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23
Q

Facultative anaerobes

A

grow via fermentation or anaerobic respiration when oxygen is not available

Growth is best where most oxygen is present, but occurs throughout tube.

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24
Q

Anaerobes

A

Unable to use oxygen and most are harmed by it

25
Q

Aerotolerant anaerobes

A

tolerate but cannot use oxygen

Growth occurs evenly oxygen has no effect

well diffused

26
Q

Microaerophiles

A

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
Q

Obligate Anaerobes

A

growth ceases in presence of O2

Growth occurs only where there is no O2

28
Q

Biofilms

A

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
Q

Sterile

A

no living microbes

30
Q

Inoculum

A

introduction of microbes into a medium

31
Q

Cultrue

A

microbes growing in or on a culture medium

32
Q

culture medium

A

nutrients prepared for microbial growth

33
Q

Agar

A

Complex polysaccharide used as solidifying agent for culture media (petri plates)
Liquefies at 100 C Boiling point
Solidifies at 40 C

34
Q

Reducing media

A

get rid of Oxygen due to cultivation of anaerobic bacteria
No O2 present

34
Q

Chemically defined media

A

exact chemical composition is known require certain type of chemical

35
Q

Complex media

A

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
Q

Capnophiles

A

require high Co2 conditions
Candle jar-Burn giving CO2

37
Q

Chemically defined

A

Growth of chemoautotrophs and photoautotrophs; microbiological assays

37
Q

Differential Media

A

Allow distinguishing of colonies of how different microbes on the same plate
changing colors

How to distinguish between species

38
Q

Selective Media

A

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
Q

Complex

A

Growth of most chemoheterotrophic organisms

40
Q

Reducing

A

Growth of bligate anaerobes

41
Q

Selective

A

Suppression of unwanted microbes; encouraging desired microbes

41
Q

Differential

A

Differentiation of colonies of desired microbes from others

42
Q

colony

A

is a population of cells arises from a single cell or spore to from a group of attached cells

43
Q

Streak plate method

A

is used to isolate pure culutres
counting bacterias

44
Q

Preserving bacterial cultures

A

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
Q

Generation time

A

Time required for a cell to divide

46
Q

Binary Fission in Bacteria

A

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
Q

Cell division generation number

A

doubles every time

47
Q

Stationary phase

A

Bacteria approach the carrying capactity

48
Q

Direct Measurement of Microbial Growth

A

count microbial cells
Plate count
Filtration
Most probable number method
Direct microscopic count

49
Q

Which of the following do you consider to be a countable plate?

A

25-3000

50
Q

Pour plate method

A

inoculate empty plate
add melted nutrient agar
swirl to mix
colonies grow on and in solidified medium

50
Q

Serial dilution

A

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
Q

The spread plate method

A

inoculate plate containing solid medium
spread inoculum over surface evenly
colonies grow only on the surface of medium

52
Q

Filtration

A

solution passed through a filter that collects bacteria
which is then transferred to a petri dish and grows as colonies on the surface

53
Q

MPN
Most Probable Number Method

A

Multiple tube test
Count positive tubes
Compare with a statistical table
(pain to do it inoculates water)

54
Q

Direct microscopic count

A

of bacteria.mL =

petroff-Hausser cell counter

# of cells counted/volume of area counted

55
Q

Indirect methods of estimating bacterial numbers

A

Turbidity
Metabolic activity
Dry weight

56
Q

Turbidity

A

measurement of cloudiness wiht a sprectrophotometer

57
Q

Metabolic ativity

A

amount of metabolic product is proportional to the number of bacteria

58
Q

Dry weight

A

bacteria are filtered, dried, and weighed used for filamentous organisms (hairy hard to count)

Microbiology (4 decks)

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