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Microbiology 251 > Chapter 7 Physical and chemical agents > Flashcards

Chapter 7 Physical and chemical agents Flashcards

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Biology 101 flashcards
1
Q

What is the destruction or removal of vegetative pathogens but not bacterial endospores only used on inanimate objects (non-living surfaces)?

A

disinfection

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2
Q

Can sterilization be used on the skin?

A

no

inanimate

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3
Q

Which Microbial control method is the complete removal or destruction of all viable microorganisms that is used on inanimate objects? (free of life, free of viruses)

A

sterilization

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4
Q

What is antisepsis?

animate

A

something used that destroys most organisms, pathogens on living surface. (skin)

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5
Q

define disinfectant

A

an antimicrobial that kills bacteria, fungi, and viruses

but not endospores

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6
Q

give 2 examples of disinfectants

A

bleach, hydrogen peroxide

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7
Q

Name the three different types of Microbial control methods (agents)

A
  • Physical agents
  • Chemical agents
  • Mechanical agents
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8
Q

What type of microbial control agents are heat and radiation?

A

physical agents

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9
Q

What is sanitization?

A

general decrease of bacterial load and debris or disinfection that meets specific public health standards
-sanitizer

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10
Q

Define degerming

A

mechanically removing some microorganisms

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11
Q

If a chemical is considered a bacteriocidal, what does it do?

A

kills microorganisms

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12
Q

If a chemical is Bacteriostatic what does it do?

A

inhibit growth, halt bacteria from reproducing

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13
Q

List the 4 things that antimicrobial agents target (in bacteria)

A
  • Cell wall (hypotonic)
  • Cell membrane or envelope
  • ** Proteins (biggest target!)
  • Nucleic Acids
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14
Q

On the list of most susceptible to most resistant, what was most susceptible to antimicrobial agents and what was most resistant?

A

Enveloped viruses = Most susceptible

Bacterial endospores = Most resistant

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15
Q

Which is more resistant (closer to bottom of list) to antimicrobial agents, Non-enveloped viruses or Mycobacteria?

A

Mycobacteria

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16
Q

Which is more resistant (closer to bottom of list) to antimicrobial agents, Fungi or Cysts of protozoa?

A

Cysts of protozoa

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17
Q

if something is “sterile”, does that mean it is safe? why?

A

No, that means it is free of life not free of molecules/chemicals

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18
Q

Do x-rays penetrate through bone?

A

no

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19
Q

What has to happen for a material to be classified as radioactive?

A

it has to be continually giving off rays/particles

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20
Q

What two types of rays/particles can remain/stay behind after radiation?

A
  • alpha

* beta

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21
Q

Which type of rays associated with radiation go through and then disappear?

A

gamma rays

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22
Q

Is Uranium radioactive and why or why not?

A

yes, because it continues emitting particles like Alpha and Beta

23
Q

Define pasteurization

A

heating up to kill pathogens below boiling point

24
Q

List the 5 methods of Physical Control

A
  1. Heat - moist and dry
  2. Cold Temperatures
  3. Desiccation
  4. Radiation
  5. Filtration
25
Q

Give the temperature, the time, and what happens/how to do it for the following.
Moist Heat:
Dry Heat:

A

Moist heat: lower temps (120-134 degrees C)
shorter exposure time ( 3-15 minutes)
Coagulation and denature of proteins
Dry Heat: mod-high temp (121 C-170 degrees C)
longer exposure time (60-600 minutes)
dehydration, alters protein structure, incineration

26
Q

Name the physical control method that involves steaming at 121 degrees C and sterilization
(they do this to our lab coats)

A

Autoclaving

27
Q

How hot must it be to boil and how long? is this disinfection or sterilization?

A

100 degrees C for 30 minutes

disinfection

28
Q

Camplyobacter, Listeria, Salmonella, and Mycobacteria can withstand which type of disinfection?
(hint: spoiled milk)

A

Pasteurization

29
Q

When you raise a liquids temperature to 134 degrees Celsius for 1-2 seconds, what type of sterilization is this?

A

Ultra High Temperature Sterilization

30
Q

How long must you expose something to Dry Heat and what temp in F?

A

1-4 hours
350 degrees F
Sterilization

31
Q

What temperature in celsius must something be incinerated at? incineration?

A

~5000 C

32
Q

What are Drying, freezing, and Lyophilization considered?

hint:what happens to bacteria when frozen

A

Bacteriostatic processes

*generally not considered disinfection

33
Q

What is associated with UV ray exposure that changes your AT sequences to TT sequences?

A

Thymine Dimer

34
Q

When are there DNA breakages, with Non-Ionizing Radiation or Ionizing radiation?

A

Ionizing Radiation

35
Q

Are X rays and Gamma rays Non-Ionizing radiation or Ionizing radiation?

A

Ionizing Radiation

36
Q

Name the two types of filtration

A
  • Liquid (pore size)

* Air (HEPA)

37
Q

What does HEPA stand for with Air Filtration?

A

High-efficiency Particulate Air Filters

38
Q

give the 3 levels of chemical decontamination

A
  • High-level
  • Intermediate-level
  • Low-level
39
Q

Which level of chemical decontamination will kill all organisms except endospores? (endospore examples: fungal spores, mycobacterium)

A

Intermediate-level

40
Q

Which level of chemical decontamination will kill endospores and can sterilize if used correctly?

A

High-level

41
Q

What will a Low-level chemical decontaminate eliminate?

A

vegetative bacteria, vegetative fungal cells, and some viruses

42
Q

Filtration is a mechanical removal method.

true or false?

A

true

43
Q

A chemical agent as a microbial control method can be either ___ or ______

A

gas or liquid

44
Q

Which chemical control type is a derivative of Phenol and is often used for surgical and hospital microbial control procedures. This chemical works against Gram-positive staphylococci and streptococci found in nurseries?

A

Bisphenols

45
Q

What part of bacteria do Biguanides primarily affect? and what are they especially effective against?

A

*bacterial cell membranes
* gram-positive bacteria
also effective against most gram-negative (except pseudomonads)

46
Q

What are Iodine and Chlorine, and what does Iodine do to bacterial cells?
what kinds of things does Iodine kill?

A

*Halogens
* Iodine impairs protein synthesis and alters cell membranes by forming complexes with amino acids and unsaturated fatty acids
* active against all kinds of bacteria
many endospores
fungi
some viruses

47
Q

What can alcohol effectively kill and how is this done?

A

bacteria
fungi
enveloped viruses
( cannot kill endospores or non-enveloped viruses )
* denatures proteins, disrupts membranes, dissolves many lipids including lipid component of enveloped viruses

48
Q

What is phenol and what is susceptible to it due to it’s ability to injure lipid-containing plasma membranes resulting in leakage of cellular contents?

A

phenol is carbolic acid

* the cell wall of mycobacteria ( TB and leprosy are rich in lipids)

49
Q

What are Quats?

what are they effective against?

A

Quaternary Ammonium compounds
* cationic detergent. most widely used surface-active agents
* strongly bacteriocidal against gram-positive bacteria, not quite as effective against gram-negative
*fungicidal, amebicidal, virucidal against enveloped viruses
Do not kill endospores or mycobacteria

50
Q

Name the most effective microbials?

A

Aldehydes

formaldehyde, glutaraldehyde

51
Q

How do Aldehydes work?

A

inactivate proteins by forming covalent cross-links with organic functional groups on proteins

52
Q

what is plasma?

A

the fourth form (state) of matter

53
Q

What are peroxygens?

A

a group of oxidizing agents

includes hydrogen peroxide and peracetic acid

Microbiology 251 (7 decks)

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