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Microbiology Exam 2 > Lecture 12 > Flashcards

Lecture 12 Flashcards

Control of Microorganisms

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Biology 101 flashcards
1
Q

How can you physically control microorganisms?

A

Heat, radiation, or filtration

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2
Q

How can you chemically control microorganisms?

A

Antiseptics, antibiotics, and disinfectants

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3
Q

Define cidal agent

A

To kill

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4
Q

What is an example of cidal cleaning?

A

Washing hands with disinfectant

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5
Q

Define static agent

A

Doesn’t kill the organism, but doesn’t allow it to grow

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6
Q

Why is static inhibition useful?

A

It gives you body a chance to destroy the bacteria before it get out of control

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7
Q

Define inhibitor agent

A

Slowing the growth of the organism

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8
Q

Define ineffective agent

A

Does nothing, possibly due to resistance

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9
Q

T or F - Resistance is the only reason for an ineffective agent

A

False, anti-microbials are ineffective against spores for reasons other than resistance.

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10
Q

Name all the effects an agent can have on bacterial growth

A

Cidal (killing), static (no growth), inhibitor (slow growth) and ineffective

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11
Q

What are the three factors pertaining to the agent’s effectiveness?

A

Amount, time, and temperature

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12
Q

What factor is concentration under?

A

Amount for chemical agents

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13
Q

What factor is intensity under?

A

Amount for physical agents

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14
Q

T or F - increasing concentration of a chemical will generally increase effectiveness

A

True

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15
Q

At what range of concentration is alcohol most effective?

A

70-95%

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16
Q

Is alcohol most effective at 100%?

A

No, you need some water to help the alcohol do its job

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17
Q

T or F - Alcohol works on vegetative cells and spores

A

False, alcohol doesn’t work on spores

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18
Q

Does increasing time increase the effectiveness if the agent is inhibitory?

A

No, it only increases effectiveness of a cidal agent

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19
Q

Time only increases the effectiveness of what kind of agent?

A

Cidal agents

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20
Q

How long must something be rubbed with alcohol to be effective?

A

About 15 seconds

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21
Q

Does increasing temperature increase effectiveness?

A

Yes

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22
Q

What does Clostridium botulinum cause?

A

Botulism

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23
Q

How long would you have to boil something at 100*C to kill spores?

A

About 5-9 hours

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24
Q

Is boiling something at 100*C for 5-9 hours considered effective?

A

No, it takes too long to kill spores

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25
Q

T or F - Heating something at 113*C for 30 minutes is sporicidal

A

False, it takes an hour for 113* objects to become sporicidal

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26
Q

How long must you heat something at 113*C to become sporicidal?

A

1 hour

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27
Q

How long must you heat something at 116*C to become sporicidal?

A

30 minutes

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28
Q

How long must you heat something at 121*C to become sporicidal?

A

15 minutes

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29
Q

How long must you heat something at 135*C to become sporicidal?

A

3 minutes

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30
Q

What objects should not be heated for sterilization?

A

Heat labile objects

31
Q

Define heat labile

A

Things, like ingredients in a medium, that break down with heat

32
Q

What was the first surgical antiseptic?

A

Phenol

33
Q

Phenol works well against what organism?

A

Staphylococcus aureus

34
Q

T or F - Phenol should be used in high concentrations

A

False, Phenol is highly caustic and should never be used in high concentrations

35
Q

A 0.1% phenol solution used indefinitely has what kind of effect?

A

Bacteriostatic

36
Q

A 1% phenol solution used for 20-30 minutes has what kind of effect?

A

It has a cidal effect

37
Q

How long does a 5% phenol solution have to be on the object to be cidal?

A

2-3 minutes

38
Q

Will warming a phenol solution increase the effectiveness?

A

Yes

39
Q

What are the factors pertaining to the organism?

A

Load, kind of organism, and pervious history of organism

40
Q

Do high loads need more time for sterilization?

A

Yes

41
Q

when you heat something to 121*C for 15 minutes, every 2 minutes you will kill what percent of the population?

A

90%

42
Q

In the 8th minute of heating to 121*C for 15 minutes in a solution with 1,000,000 viable organisms, how many will be dead?

A

900,000+90,000+9,000+900= 999,900

43
Q

In the 2nd minute of heating to 121*C for 15 minutes in a solution with 1,000,000 viable organisms, how many will be dead?

A

90%, 900,000

44
Q

In the 4th minute of heating to 121*C for 15 minutes in a solution with 1,000,000 viable organisms, how many will be dead?

A

900,000 (2nd minute) + 90,000 (4th minute), total of 990,000

45
Q

In the 6th minute of heating to 121*C for 15 minutes in a solution with 1,000,000 viable organisms, how many will be dead?

A

900,000 (2nd minute) + 90,000 (4th minute) + 9,000, totaling 999,000 dead

46
Q

In the 10th minute of heating to 121*C for 15 minutes in a solution with 1,000,000 viable organisms, how many will be remaining?

A

10 organisms remaining

47
Q

If in the 12th minute of heating to 121*C for 15 minutes in a solution with 1,000,000 viable organisms, there is 1 organism left, why do we keep heating the solution till 15 minutes?

A

To ensure that last organism is killed

48
Q

What are 3 factors pertaining to the type of organism?

A
  1. Gram (+ vs -)
  2. Vegetative cells vs. spores
  3. Virus vs. bacteria
49
Q

How does gramitivity make a difference for sterilizing?

A

Gram - outer membrane gives the organism more resistance

50
Q

T or F - Gram + organisms are more resistant than gram -

A

False, the gram - outer membrane allows the g- to be more resistant

51
Q

How does vegetative cells vs. spores determine effectiveness?

A

Heating cells will take less time to kill them than heating spores

52
Q

Why are viruses harder to kill?

A

They are resistant to phenol and do not dry easily

53
Q

How long does it take for Hepatitis B to desiccate?

A

About 1 week

54
Q

T or F - Younger cells are more resistant to chemicals

A

False, mature cells are more resistant to chemicals

55
Q

Why are younger cells more sensitive to chemicals?

A

They are still making their cell wall, and have a higher rate of metabolism

56
Q

Why are old cells more sensitive to chemicals?

A

They have been sitting in toxins and have become weakened

57
Q

What 4 factors pertain to the nature of the environment?

A
  1. Penetration
  2. Inactivation
  3. pH
  4. Enzymes
58
Q

What does penetration refer to when discussing factors of the environment?

A

Density or volume of the material and how it effects effectiveness

59
Q

T or F - Increasing the density or volume decreases the effectiveness of the agent.

A

True

60
Q

T or F - Decreasing the volume or density decreases the effectiveness of the agent

A

False, increasing the volume/density decreases effectiveness

61
Q

What is an example of a factor of penetration?

A
  1. Ultraviolet light

2. Agar or broth

62
Q

Is ultraviolet light penetrative?

A

No, it only takes a little bit of sunscreen to no longer be effected by ultraviolet light

63
Q

Can ultraviolet light kills spores?

A

Yes

64
Q

If you have more volume of material, how does that effect the amount of time something must be placed into an autoclave for?

A

It increases the time

65
Q

Define colloid

A

Any particle that is too large to fo into solution, yet small enough that it remains suspended in the solution

66
Q

Give examples of colloids

A

Bacteria, blood cells, vomit, feces, chlorine

67
Q

Colloids are an example of what kind of factor pertaining to the environment?

A

Inactivation

68
Q

T or F - pH is unable to inactivate certain particles

A

False

69
Q

T or F - Iodine acid is less effective in alkaline conditions

A

True, it is most effective in acidic conditions

70
Q

Define alkaline

A

Basic

71
Q

To what organism are Carbapenems related to?

A

Penicillin

72
Q

Why include carpenems in medication?

A

Kidneys will break down the carbapenems instead of the medication

73
Q

What enzyme in kidneys breaks down carbapenems?

A

Dipeptidases

Microbiology Exam 2 (11 decks)

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