Chapter 7 - Control of Microbial Growth

Question 1

What kills all microorganisms?

Answer 1

Sterilization

Question 2

What is disinfection?

Answer 2

Destruction of pathogenic organisms on an inert surface

Question 3

What is a danger of disinfection?

Answer 3

It can damage living tissue

Question 4

What is Antisepsis?

Answer 4

The destruction of pathogenic organisms on living tissue

Question 5

What is sanitizer?

Answer 5

A product that lowers the number of microbials to safe levels as set by public health

Question 6

What does it mean if something is septic?

Answer 6

It is contaminated with pathogenic microorganisms

Question 7

What is aseptic?

Answer 7

Free of pathogenic microorganisms

Question 8

What is degermination?

Answer 8

The mechanical removal of microorganisms

Question 9

What form of microbial growth control is hand soap?

Answer 9

Degermination

Question 10

What does the -cide ending mean?

Answer 10

Kill

Question 11

What does the -stat ending mean?

Answer 11

Slow, inhibit

Question 12

What does the -lytic ending mean?

Answer 12

Rupture of cell (kills most of the time

Question 13

What 4 factors affect antimicrobial effectiveness?

Answer 13

1. Concentration of microbes - less cells, more effective
2. Environmental factors - temp., pH, pure or mixed culture
3. Time of exposure
4. Specific microbial characteristics - resistance to death

Question 14

What is Decimal Reduction Time?

Answer 14

The time in which 90% of microbial population will be killed at a given temperature

Question 15

If the temperature is low, what will happen to the Decimal Reduction Time (D)?

Answer 15

It will increase

Question 16

What is an example of moist heat that discourages microbial growth?

Answer 16

Autoclave - uses water, heat, pressure

Question 17

What is an example of dry heat antimicrobial?

Answer 17

Oven - used in clinical setting for glassware and metal

Question 18

What is the lowest temperature at which all microorganisms are destroyed in 10 minutes called?

Answer 18

Thermal Death Point

Question 19

What is the Thermal Death Time?

Answer 19

The minimum amount of time at which all microorganisms are destroyed at a a given temperature

Question 20

What is the x-ray an example of?

Answer 20

Ionizing radiation

Question 21

What is ionizing radiation?

Answer 21

x-ray, gamma ray, electron beams; form hydroxyl free radicals

Question 22

What is non-ionizing radiation?q

Answer 22

UV, damages cell components, ex. sunburn, damage nucleic acids

Question 23

What is pasteurization?

Answer 23

not sterilizing, heat decreases number of microorganisms to a safe level using low heat

Question 24

What is the use of membrane filters to retain certain organisms then treat and destroy or lower cell numbers called?

Answer 24

Filtration

Question 25

How do toxic chemicals work to combat microbial growth?

Answer 25

gasses - toxic and impede growth

antimicrobials - don’t necessarily kill organisms, concern for environment because they are harmful to living things

Question 26

What is dessication?

Answer 26

Dehydration of microbes

Question 27

What form of temperature lowering is most harmful to microorganisms and why?

Answer 27

Slow-low drop, because it causes crystals to form in the cell

Question 28

What is one way to dehydrate a microorganism?

Answer 28

Placing them in a hypertonic solution (osmotic pressure)

Question 29

What is the name of any chemical substance used to prevent or treat a wide range of problems?

Answer 29

Chemotherapeutic agent

Question 30

What form of medicine is made by a living organism?

Answer 30

Antibiotic

Question 31

What is the name of the lowest concentration of chemotherapeutic agent or antimicrobial that will kill a microorganism?

Answer 31

Minimum Inhibitory Concentration (MIC)

Question 32

What are 2 ways to evaluate antimicrobials?

Answer 32

1. Use dilution test

2. Disk diffusion method

Question 33

How does the Use Dilution Test work?

Answer 33

Metal rings are dipped in cultures, then soaked in antimicrobial for 10 minutes, rings are then placed on growth media and incubated; look for growth

Question 34

How does the Disk Diffusion Method work?

Answer 34

Filter paper disks are soaked in anti-microbial and placed on petri dish of microorganisms, incubated, if it works there is a clear zone on the plate