Chapter 11: Physical and Chemical Agents of Control

Question 1

Sterilization

Answer 1

a process that destroys all viable microbes from the surface, including viruses and endospores

Question 2

Disinfection

Answer 2

using a chemical to destroy vegetative pathogens, not endospores ; in inanimate objects

Question 3

Antiseptic

Answer 3

disinfectants applied directly to exposed to skin

Question 4

Sanitization

Answer 4

(mechanical rubbing ) any cleansing technique that mechanically removes microbes

Question 5

What are the highest resistance microbes?

Answer 5

Prions, bacterial endospores

Question 6

Moderate resistance microbes

Answer 6

Pseudomonas sp.,
mycobacterium tuberculosis
staphylococcus aureus
protozoan cysts

Question 7

Least resistances microbes

Answer 7

Most bacterial vegetative cells
fungal spores and hyphae, yeast
enveloped viruses
protozoan trophozoites

Question 8

what are the cellular target of chemical and physical agents?

Answer 8

Cell wall
cell membrane
protein & nucleic acid synthesis
Proteins

Question 9

What are the methods of physical control?

Answer 9

Heat- moist & dry
Cold temperatures 
Desiccation
Radiation 
Filtration

Question 10

Moist heat methods of disinfection include?

Answer 10

• Steam under pressure : Autoclave

- Boiling

Question 11

Autoclave

Answer 11

15 psi/ 121C/15min

Question 12

Boiling

Answer 12

at 100C for 30mins to destroy non-spore forming pathogens

Question 13

Microbiostatic

Answer 13

slows the growth of microbes

Question 14

Example of microbiostatic

Answer 14

refrigeration and freezing

Question 15

Desiccation/ dehydration

Answer 15

• gradual removal of water from cells , leads to metabolic inhibition.
• not effective microbial control

Question 16

lyophilization

Answer 16

freeze drying; preservation