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MBIO 1010 > Metabolic Pathways, Optimal Growth, and Sterilization Techniques > Flashcards

Metabolic Pathways, Optimal Growth, and Sterilization Techniques Flashcards

Lectures 21-23

1
Q

What is a Psychrophile?

A

Microorganism that grows well at low temperatures (<20 C)

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2
Q

What is a Mesophile?

A

Microorganism that grows well at mid-range temperatures.

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3
Q

What is a Thermophile?

A

Microorganism that grows well at high temperatures (45 C- 80 C).

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4
Q

What is a Hyperthermophile?

A

Microorganism that grows well at very high temperatures (>80 C).

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5
Q

What is a psychotolerant microorganisms?

A

Can grow at 0 C but prefer temperatures between

20 C- 40 C.

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6
Q

True or False: Above 65 C only eukaryotic life exists.

A

False: Above 65 C only prokaryotic life exists.

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7
Q

What is an Acidophile?

A

Grows best at a ph <6.

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8
Q

What is an Alkaliphile?

A

Grows best at a ph >9.

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9
Q

What is water activity (aw)?

A

Water availability: expressed in physical terms-
Defined as the ratio of vapor pressure of air in equilibrium with a substance or solution to the vapor pressure of pure water

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10
Q

Where does water want to go- to higher solute concentrations or lower solute concentrations? What does it want to produce by moving?

A

Water wants to go to the high solute concentrations to create turgor pressure.

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11
Q

What is a halophile?

A

Microorganism that grows well in a saline filled environment.

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12
Q

What is an extreme halophile?

A

Requires a 15-30% saline environment to grow.

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13
Q

What is a halotolerant microorganism?

A

A microorganism that can tolerate low water activity but grows best at lower solute concentrations.

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14
Q

What is an osmophile?

A

Grows well with a high sugar solute.

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15
Q

What is a xerophile?

A

Grows well in dry environments.

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16
Q

What do honey, jams, jellies, jerky, and salted cod all have in common?

A

Don’t have a lot of microorganisms growing in them due to lack of water activity and lack of nutrients.

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17
Q

What is an obligate aerobe? In which zone will it grow in a thioglycolate broth tube?

A

An organism that requires oxygen to live. It will grow only in the oxic zone at the top of the thioglycolate broth tube.

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18
Q

What is a strict anaerobe? Which zone will it grow in in a thioglycolate broth tube?

A

An organism that does not require oxygen to live and may by killed by it. It will grow only in the anoxic zone at the bottom of the thioglycolate broth tube.

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19
Q

What is a facultative aerobe? Which zone will it grow in in a thioglycolate broth tube?

A

An organism that can grow without oxygen but will use it when it is available. It will grow throughout the thioglycolate broth tube, but optimal growth occurs in the oxic zone where oxygen is present.

20
Q

What is a aerotolerant anaerobe? Which zone will it grow in in a thioglycolate broth tube?

A

An organism that can grow in the presence and tolerate oxygen, but will not use it. It will grow well all throughout the thioglycolate broth tube, but will not use any oxygen.

21
Q

What is a microaerophile? Which zone will it grow in in a thioglycolate broth tube?

A

An organism that can use oxygen when the oxygen’s levels are reduced from the air. It will grow only in the narrow band between the oxic and anoxic zone of the thioglycolate broth tube. It needs oxygen for aerobic respiration, but is killed by atmospheric levels of oxygen.

22
Q

What are the toxic forms of oxygen that can be formed inside a cell?

A

Superoxide anion
Hydrogen peroxide
Hydroxyl radical

23
Q

What are the enzymes present to neutralize the toxic forms of oxygen formed inside a cell? Which type of metabolic pathway lacks these enzymes?

A 
Catalase 
Peroxidase 
Superoxide dismutase 
Superoxide reductase
Obligate anaerobes usually lack these enzymes.
24
Q

Which oxygen neutralizing enzymes have peroxide in their products?

A

Superoxide dismutase
Superoxide dismutase/ catalase in combination
Superoxide reductase

25
Q

What oxygen neutralizing enzymes have peroxide in their reactants?

A

Catalase

Peroxidase

26
Q

What sterilization?

A

The killing or removal of all viable organisms within a growth medium.

27
Q

What is inhibition?

A

Effectively limiting microbial growth

-No killing taking place

28
Q

What is decontamination?

A

The treatment of an object to make it safe to handle.

29
Q

What is disinfection?

A

Removes all pathogens, but not necessarily all microorganisms.

30
Q

What is pasteurization? What is the difference between pasteurization and sterilization?

A

The process of using precisely controlled heat to reduce the microbial load in heat-sensitive liquids. Unlike sterilization it does not kill all the microorganisms.

31
Q

What temperature and pressure does an autoclave sterilize, and what is the temperature of the water?

A

When the water reaches 100 C, the autoclave sterilizes at 121 C for 15 min at 15 pounds per square inch.

32
Q

What kind of radiation can reduce microbial growth?

A

Microwaves, UV, X-rays, gamma rays, and electrons

33
Q

What is ionizing radiation?

A

Electromagnetic radiation that produces ions and other reactive molecules generates electrons, hydroxyl radicals, and hydride radicals.

34
Q

What does filtration avoid? What is the pore size used and not used?

A

Heat to not damage sensitive liquids and gases. 0.5 um not used, 0.2 um used.

35
Q

What are antimicrobial agents?

A

Bacteriostatic: prevents cell growth as long as the antimicrobial agent is present
Bacteriocidal: kills the cells (does not lyse them) Bacteriolytic: kills and lyses the cells

36
Q

What is Minimum inhibitory concentration (MIC)?

A

The smallest amount of an agent needed to inhibit growth of a microorganism.

37
Q

What are the steps to Disc diffusion assay?

A 
Uses solid media 
Antimicrobial agent is added to filter paper disc  
The MIC is reached at some distance 
Forms a zone of inhibition 
Area of no growth around disc
38
Q

What is a sterilant?

A

destroys all microorganisms including endospores

39
Q

What is a disinfectant?

A

kills microorganisms but not all endspores.

-Used on inanimate objects

40
Q

What is a sanitizer?

A

reduces the numbers of microorganisms on surfaces (e.g. hand sanitizers)

41
Q

What is an antiseptic?

A

kills or inhibits the growth of microorganisms (non-toxic enough to be applied on living tissue (e.g. mouth wash))

42
Q

What two categories can antimicrobial agents be split into?

A

1.Products used to control microorganisms in commercial and industrial applications
Ex) chemicals in foods, air conditioning cooling towers, textile and paper products, fuel tanks
2. Products designed to prevent growth of human pathogens in inanimate environments and on external body surfaces

43
Q

What is LTLT (low-temperature/long-time)?

A

63 C for 30 min

44
Q

What is HTST (high-temperature/short-time)?

A

72 C for 15 seconds

45
Q

What is UHT (ultra high-temperature/short time)?

A

100 C for 3 seconds

MBIO 1010 (14 decks)

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