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Microbiology > Chapter 3- pt 2 Microorganisms And microbiology > Flashcards

Chapter 3- pt 2 Microorganisms And microbiology Flashcards

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Biology 101 flashcards
1
Q

Acidophiles

A

Organism that grows best at low ph (less than 6)

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2
Q

Organisms that grow best at high ph (more than 9)

A

Alakaliphiles

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3
Q

Microbial culture contains buffers to maintain constant pH. Why?

A

Each organism has an optimal ph for growth
Some bacteria produce acids that decreases pH
Some bacteria produce amino acids that increases pH

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4
Q

What is aW (water activity)?

A

Amount of free water. Available water for microorganism
The amount of water that is interacting with ions and polar compound solutions.

Ratio or vapour pressure of air in equilibrium with a substance or solution of vapour pressure of pure water

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5
Q

Cytoplasm (inside of cell) has higher solute concentration than environment. Where will water move?

A

Water will move into cells resulting to TURGOR PRESSURE

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6
Q

Positive water balance

A

Turgor pressure

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7
Q

Cytoplasm (inside of cell) has lower solute concentration than environment (higher solute concentration). Where will water move?

A

Water will move out of cell to environment

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8
Q

Microorganism that grows best at reduced water potential. Have specific requirement for NACL.

A

Halophiles

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9
Q

Organism that requires high levels of NaCl for growth. At what percent?

A

Extreme halophiles

15-30%

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10
Q

Halotolerant

A

Organism that can tolerate some reduction in water activity of environment but generally grow best at lower solute concentrations

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11
Q

Osmophiles

A

Microorganism that can grow at high sugar as solute

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12
Q

Xerophiles

A

Organism that able to grow in very dry environments

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13
Q

Compounds used by cells to counteract low water activity in surrounding environment

A

Compatible solutes

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14
Q

Organism that requires oxygen to live

A

Obligate aerobes

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15
Q

Strict anaerobe

A

Do not require o2. Dies at presence of o2

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16
Q

Facultative aerobe

A

Can live with or without 02, but grows well if presence of 02

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17
Q

Aeroloterant aerobes

A

Can tolerate o2 and grow in presence even though they cannot use it.

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18
Q

Microaerophiles

A

Can use oxygen when its present at levels reduced from that in air (2-10%)

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19
Q

Differences in oxygen use/ tolerance can be distinguish sed using _____

A

Thioglycolate broth

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20
Q 
State at which zone they grow in thioglycolate broth
Obligate aerobe
Strict anaerobe
Facultative anaerobe
Microaerophile
Aerotolerant anaerobe
A

Obligate aerobe - oxic zone (top)
Strict anaerobe- anoxic zone (bottom)
Facultative anaerobe - throughout tube but better in oxic (top)
Microaerophile -narrow band between oxic and anoxic
Aerotolerant anaerobe- grows well throughout tube

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21
Q

Chemicals used that can be add in media to reduce oxygen

A

Reducing agent

22
Q

Toxic forms of oxygen

A

Superoxide anion
Hydrogen peroxide
Hydroxyl radical

23
Q

Enzymes to neutralize toxic forms of oxygen

A

Catalase
Peroxidase
Superoxide dismutase
Superoxide reductase

24
Q

What types of microorganism lacks enzymes that can neutralize toxic forms of oxygen

A

Obligate anaerobes

25
Q

Growth control by heat examples of general principles

A

Sterilization
Inhibition
Decontamination
Disinfection

26
Q

Kills all viable microorganism within a growth medium

A

Sterlization

27
Q

Inhibition

A

Limits microbial growth. No killing

28
Q

Treatment of an obj make it safe to handle

A

Decontamination

29
Q

Directly targets removal of all pathogens, not necessarily all microorganism

A

Disinfection

30
Q

Most widely used method of controlling microbial growth

A

Heat sterilization

31
Q

Decimal reduction time

A

Time it takes for a 10 fold reduction in bacterial numbers

32
Q

Endospores

A

Resistant cells, that can survive heat that would rapidly kill vegetative cells

33
Q

Pasteurization

A

Use of precise controlled heat to reduce microbial load in heat sensitive liquids. Does not kill microorganism

**different than sterlization

34
Q

LTHT and STHT

A

63C, 30 mins; 72C, 15 secs

35
Q

Sealed device that uses steam under pressure. Allows temp of water to reach above 100C.
Uses moist heat at what temp? And time?

A

Autoclave

121C for 15 mins

36
Q

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

A

Ionizing radiation

37
Q

Filtration and give example.

A

Avoid use of heat on sensitive liquids and gases. Uses pores of filters.

HEPA FILTER AND MEMBRANE FILTER

38
Q

Two examples of pore sizes

A

5 and 02. Micrometer

39
Q

Antimicrobial agents can be classified as

A

Bacteriostatic
Bacteriocidal
Bacteriolytic

40
Q

Prevents microbial growth as long as Antimicrobial agent is present

A

Bacteriostatic

41
Q

Antimicrobial agent that kills the cell but does not lyse them

A

Bacteriocidal

42
Q

Bacteriolytic

A

Antimicrobial agent that kills the cell and lyse them

43
Q

Minimum inhibitory concentration (mic)

A

Smallest amt or an agent needed to inhibit growth of microorganism

44
Q

Use solid media. An antimicrobial agent that is added to filter paper disc. Forms zone of inhibition

A

Disc diffusion assay

45
Q

Antimicrobial microbial agents can be classified into 2 categories

A

Products to control MO in commercial and industrial applications
Products designed to prevent growth of human pathogens inanimate environments and on external body surfaces

46
Q

Example of products to prevent growth of human pathogens in inanimate envr and ext body surfaces.

A

Sterilant
Disinfectant
Sanitizer
Antiseptic

47
Q

Destroys all MO including endospores

A

Sterilant

48
Q

Kills MO but not all endospores. Used on inanimate obj

A

Disinfectant

49
Q

Reduces the number of MO on surfaces

A

Sanitizers

50
Q

Kills or inhibit growth of MO, but sufficiently non toxic to be applied on living tissues (eg. Mouth wash)

A

Antiseptic

Microbiology (6 decks)

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