microbio feb21

Question 1

Physical Control
Application of Heat

Answer 1

Moist Heat
Dry Heat

Question 2

water aids in the disruption of covalent bonds

Answer 2

moist heat

Question 3

kills vegetative forms but not spores and viruses

Answer 3

boiling

Question 4

boiling time and temp

Answer 4

100°C 15 – 30 minutes

Question 5

steam for 30mins , 3 days

Answer 5

tyndallization

Question 6

75-80°C for 2hrs , 3 days

Answer 6

inspissation

Question 7

fractional sterilization

Answer 7

Tyndallization
inspissation

Question 8

steam under pressure

Answer 8

autoclaving

Question 9

autoclave time, temp, pressure

Answer 9

121°C at 15 psi for 15 – 30 minutes

Question 10

sterilization for milk

Answer 10

pasteurization

Question 11

pasteurization time and temp

Answer 11

60°C , 30min

Question 12

kills by oxidation

Answer 12

dry heat

Question 13

time depends on the penetration of heat on objects to be sterilized
;
for metals and glasswares

Answer 13

hot air oven

Question 14

hot air oven time and temp

Answer 14

160 – 180°C for 1–2 hrs

Question 15

usually for inoculating loops and needles

Answer 15

Direct Flame/ Incineration

Question 16

Indians used to dry their food under the sun; lack of water prevents multiplication

Answer 16

desiccation

Question 17

3 types of radiation

Answer 17

UV light
microwave radiation
ionizing radiation

Question 18

DNA replication is inhibited; forms thymine dimmers; can damage the cornea and skin

Answer 18

UV light

Question 19

dislodge electrons from atoms and form ions; cause mutations in DNA and produce peroxides; used to sterilize medical supplies

Answer 19

ionizing radiation
(x-rays, gamma rays, etc)

Question 20

heat is absorbed by water molecules; may kill vegetative cells in moist foods

Answer 20

microwave radiation

Question 21

physical separation of microbes from liquid

Answer 21

filtration

Question 22

by plasmolysis

Answer 22

osmotic pressure

Question 23

mechanical methods that disintegrate bacteria

Answer 23

Sonic Vibration, Trituration, Agitation

Question 24

sound waves

Answer 24

sonic vibration

Question 25

grinding

Answer 25

trituration

Question 26

shaking

Answer 26

agitation

Question 27

preservation method

Answer 27

lyophilization/ freeze-drying

Question 28

a chemical substance that prevents growth of bacteria by either inhibiting or destroying microbes

Answer 28

antiseptic

Question 29

used on the surface of skin or mucous membranes

Answer 29

antiseptic

Question 30

kills many but not all microbes

Answer 30

disinfectant

Question 31

aims to kill disease-causing microbes but not spore formers

Answer 31

disinfectant

Question 32

used on inanimate objects

Answer 32

disinfectant

Question 33

agents that inhibit the growth of bacteria

Answer 33

bacteriostatic

Question 34

agents that kill bacteria

Answer 34

bactericide

Question 35

variables of disinfection

Answer 35

1. Concentration 2. Time 3. Temperature 4. pH

Question 36

formula for

Answer 36

n=1/CT where: N = no. of surviving bacteria C = concentration T = time

Question 37

the lowest temperature at which all the microbes in a liquid culture will be killed in 10 mins

Answer 37

Thermal Death Point

Question 38

the length of time required to kill all bacteria in a liquid culture at a given temperature

Answer 38

Thermal Death Time

Question 39

the length of time in which 90% of a bacterial population will be killed at a given temperature

Answer 39

Decimal Reduction Time

Question 40

burns organisms and physically destroys them

Answer 40

incineration

Question 41

smaller scale of inceneration

Answer 41

direct flaming

Question 42

the process of extreme drying

Answer 42

dessication

Question 43

Physical Control COLD

Answer 43

1. freezing and refrigeration 2. lyophilization

Question 44

reduces metabolic rate of most microbes so they cannot reproduce or produce toxins

Answer 44

refrigeration

Question 45

refrigeration temp

Answer 45

0-7°C

Question 46

freezing that does not kill most microbes

Answer 46

flash freezing

Question 47

freezing that is more harmful because ice crystals disrupt cell structure

Answer 47

slow freezing

Question 48

a process in which water is removed from a product after it is frozen and placed under a vacuum, allowing ice to change directly from solid to vapor without passing through a liquid phase

Answer 48

lyophilization

Question 49

what are more capable than bacteria when growing in materials with low moisture or high osmotic pressure

Answer 49

molds and yeasts