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Microbiology > Microbial Nutrition and Growth > Flashcards

Microbial Nutrition and Growth Flashcards

1
Q

Which of the following culture methods must be done for an organism that cannot exist in the presence of oxygen?

A

Reducing media in an airtight jar

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2
Q

Organisms that preferentially grow in the ice sheets of Antarctica are described as

A

psychrophiles

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3
Q

Quorum sensing is

A

the ability to respond to changes in population density

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4
Q

Why is optimal temperature important to maintain in regard to proteins?

A

It keeps proteins from denaturing.

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5
Q

Microorganisms requiring a large number of growth factors for their optimal growth are referred as

A

Fastidious Organisms

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6
Q

In a defined medium

A

the exact chemical composition of the medium is known

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7
Q

Why is NADH an important growth factor for microorganisms?

A

It serves as an electron carrier in energy-producing pathways.

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8
Q

What is the role of oxygen in aerobic metabolism?

A

It serves as a final electron acceptor in electron transport.

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9
Q

For an organism to be pathogenic to humans it would likely need to be a

A

neutrophile

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10
Q

An organism that uses CO2 and acquires energy from hydrogen would be classified as a

A

chemoautotroph

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11
Q

Barophiles

A

cannot cause diseases in humans

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12
Q

A media that can grow only certain types of microbes is best defined as

A

selective

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13
Q

A microbe that can tolerate high salt concentration is known as a

A

facultative halophile

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14
Q

In a microbiology laboratory, what does culturing mean?

A

Culturing is the act of growing microbes in a scientific setting.

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15
Q

Colony (genetic material same)

A

An aggregation of cells arising from a single parent cell

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16
Q

Biofilm (form interactions within organism)

A

Collection of microbes living on a surface in a complex community

17
Q

Nutrients necessary for growth

A

Carbon, oxygen, nitrogen, and hydrogen are necessary for cell growth and cell production)

18
Q

Organism based on used of carbon

A

Autotrophs and heterotrophs

19
Q

Organism based source of energy

A

Chemotrophs (anaerobic and aerobic respiration or fermentation will be on this one) and phototrophs

20
Q

Oxygen is essential for obligate aerobes

A

Oxygen is deadly for obligate anaerobes

21
Q

Aerobes

A

requires oxygen to survive must be able to handle the toxic fermentation of oxygen
Ex:Bacillus

22
Q

Anaerobes

A

Doesn’t require oxygen to survive
Ex: Clostridium sporogenes

23
Q

Facultative anaerobes

A

Prefer oxygen but they can survive without it
Ex: Escherichia Coli and Staphylococcus

24
Q

Aerotolerant Anaerobes

A

Do not have a preference for oxygen where there’s less competition is streptococci an streptococci pneumonia
Ex:Streptococcus pyogenes

25
Q

Microaerophiles

A

Requires low levels of oxygen even lower than the atmosphere

26
Q

Chemical and energy requirements for growth

A

-Nitrogen levels need to be 70 to 80% of the atmosphere made of nitrogen
-Nitrogen fixation
-Trace elements molecules needed
-Growth factors
(fastidious organisms really difficult to grow syphilis can growth on the human body unique organisms can’t grow in any other medias)
-Temperature
- If too low, membranes become rigid and fragile.
– If too high, membranes become too fluid. (Death of cell both can cause this)
Thriving and Surviving is different

27
Q

Five categories of Microbes

A

-Psycholophiles can trive in the refrigerator can’t survive human temperature like algae
-Psycholtolerants can survive in the refrigerator and can survive the human body temperature
-Mesophiles boil time becomes important
-Thermophiles can trive in hot temperatures but wil not survive the human body
-Hyperthernophiles organisms like archae that survive in really hot temerpatures

28
Q

Physical requirements from growth

A

-Neutrophiles the human neutral pH
-Acidophikes vagina yeast infection candida albicans
-Alkaliphiles cholera molds prefer sugar and acid organims
-Baraphiles live under extreme pressure like organims that live under the ocean
Osmotic pressure(limiting to kills them with water)
-Hypotonic lower osmotic pressure which causes water to enter cell
– Hypertonic higher osmotic pressure which causes water to leave the cell
-Hydrostatic pressure organism that can survive the pressure from the ocean

29
Q

Synergistic relationships

A

cooperative relationships both of the organisms are going to benefit but relationships are required to survive
Ex: Biofilms organisms will benefit when attached to biofilms ocean rocks green stuff. Complex relationships among numerous
microorganism and many organisms are more harmful as a part of a biofilm

30
Q

Symbiotic relationships

A

Need a relationship to survive

31
Q

Quorum sensing

A

Increase has density of the environment increases

32
Q

Insolation techniques to obtain CFU a coloning forming unit

A

-Streak plates culture will grow only in the media
-Pour plates culture will grow through the media

33
Q

Complex Media

A

Nutrients commonly derived from breakdown of yeast, beef ,soy and proteins

34
Q

Selective media

A

Contain substances that favor or inhibit growth of particular microorganisms
Ex: Fungi thrives in acidic environments with acidophilus

35
Q

Differential media

A

Different bacteria growing on the media are distinguished by Presence of visible changes in the medium like from red to yellow
Differences in the appearance of colonies
Blood Agar hemolysis is not selective anything can grow in different media physical changes will appear different in colors from yellow to red when bacteria grow

36
Q

A typical growth curve number of live cells and time

A

at the starting there’s
1. Lag phase
2. Log phase
3. Stationary phase
4.Death decline phase

37
Q

Direct Methods not requiring incubation

A

Coulter counter
-counts cells as they interrupts an electrical current
Flow cytometry
-detects changes in light transmission as cells pass a detector
Microscopic counts

38
Q

Direct methods requiring incubation

A

Serial dilution and viable plate counts
Membrane filtration
Estimating the number of microorganisms is useful
* Determine severity of certain infections
* Determine effectiveness of food preservation techniques
* Measure the degree of contamination of water supplies
Evaluate disinfectants and antibiotics

39
Q

Indirect methods

A

Turbidity
Often the more turbid a culture, the greater the bacterial population
-Measuring Microbial Growth
-Metabolic activity
-Dry weight
-Molecular methods
-Isolate D N A sequences of unculturable prokaryotes

Microbiology (4 decks)

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