Mcrobiology Chapter 7 Flashcards Preview

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Flashcards in Mcrobiology Chapter 7 Deck (30):
1

Alcohol

Alcohol is an organic solvent disinfectant that denatures proteins and disrupts cell membranes.

2

Aldehydes

A very strong group of disinfectants that denature protiens by cross-linking the R-groups of amino acids and includes the sterilizing agent gluteraldehyde.

3

Ammonia

Quaternary Ammonium Compound- catonic amd works best against Gram (+) as opposed to Gran (-) bacteria.

4

Antiseptic

An antiseptic is an agent used to decrease tha number of organisms on living tissue.

5

Autoclave

A method used for sterilization(kills everything including endospores) involving a moist heat under pressure.

-121 c and 15 psi for 20 minutes.

-items are wrapped to ensure they remain sterile

-heat sensitive materials cannot be used during this

- EX: canned foods and glassware

6

Oligodynamic Action

-reacts with chemical groups on proteins 

- inactivates enzymes

-effective in small concentrations

7

organic solvents

chloroform, toluene, alcohols (no residue)

* 70% alcohol is the most effective concentration.

8

osmotic pressure

creates a hypertonic environment (desiccation) (preserve)

9

oxidizing agents

ozone and peroxide

(denatures proteins)

10

pasteurization

mild heating- that will kill most disease and spoilage causing organisms

11

Wjo

12

AM

Which of the following substances can sterilize?

A) Alcohol 

 B) Phenolics  

C) Ethylene oxide 

 D) Chlorine

  E) Soap
  

C) Ethylene oxide 

13

AM

Which of the following affects the elimination of bacteria from an object?
A) Number of bacteria present  C) Temperature  E) All of theses
B) Presence of organic matter  D) pH

 

  E: All the conditions listed affects the elimination of bacteria from an object.

14

AM

Which of the following is a limitation of the autoclave?
A) Requires a long time to achieve sterilization
B) Cannot inactivate viruses
C) Cannot kill endospores
D) Cannot be used with heat-labile materials
E) Cannot be used with glassware

 

 D: The autoclave uses high temperatures that would melt heat-labile materials.

15

16

17

G.L. Which microorganism is the most resistant to chemical biocides?

 

a) Gram + bacteria

b) Gram - bacteria

c) Mycobacteria

d) Vegetative protozoa

 

G.L. c) Mycobacteria

18

G.L. Which of the following would qualify as liquid sterilizing agent?

 

a) Alcohol

b) Chlorine

c) Gluteraldehyde

d) Phenol 

G.L. c) Gluteraldehyde

19

 

 

G.L. Degermination

 

G.L. Mechanical removal, rather than killing, of most of the microbes in the limited area. (ex. before recieving injection or ivy)

 

 

20

 G.L. Which method is widely used to control microbes in the air ( hospital rooms, operating rooms, nurseries)?

a) Osmotic pressure

b) UV light

c) Desiccation

d) Incineration

 

 

 

G.L. b) UV light

21

 G.L. What is the recommended optimum concentration in order for ethanol to be the most effective?

a) 99.99%

b) 85%

c) 50%

d) 70%

 

 

 

G.L. d) 70%

22

Which of the following is the best method to sterilize heat-labile solutions?
A) Dry heat    C) Autoclave  E) Membrane filtration
B) Pasteurization

(AW)
 

E: The only two methods listed that sterilize are autoclaving and membrane filtration and autoclaving cannot be used for heat-labile solutions.

23

Which of the following substances can sterilize?
A) Alcohol    C) Ethylene oxide   E) Soap
B) Phenolics    D) Chlorine

(AW)
 

C: The only agent listed that sterilizes is the gaseous agent ethylene oxide.

24

Which of the following substances is used for surgical hand scrubs?
A) Phenol    C) Chlorhexidine   E) Glutaraldehyde
B) Chlorine bleach  D) Soap

(AW)
 

C: Chlorhexidine is a surgical hand scrub.

25

 Which of the following does NOT achieve sterilization?
A) Dry heat    C) Pasteurization   E) Autoclave
B) Formaldehyde   D) Ethylene oxide

(AW)
 

C: Pasteurization uses a temperature too low to sterilize.

26

If you were preparing nutrient agar at home and didn’t have an autoclave, what could you use to sterilize the nutrient agar?
A) Bleach  
B) Boiling for 1 hour 
C) Hydrogen peroxide
D) Oven at 121°C for 1 hour 
E) Pressure cooker at 121°C for 15 minutes

(AW)
 

E: An autoclave is essentially a pressure cooker that produces steam under pressure

27

RM

When added to water, chlorine forms what type of acid?

Hypochlorous acid

28

JP

What Substances are commonly used in the process of preservation (in terms of food preservation)?

(Salt,Sugar) are both used on foods to prevent deteroration by microbial action.

29

JP

What process does isopropyl alcohol use to break down membranes and disinfect?

Hydrolysis, it uses the water(hydro) found in the mixtures of isopropyl alcohol (70/30) to burst the cells(lysis). 

30

JP

If a person has thrown up, why is it neccessary to clean up the extraneous material (vomit) before sterilizing the area with a chemical agent?

Because the amount of expelled substance will denature the chemical used to sterilize, so its best to clean up then sanitize the area with cleaner.