Growth and Control

Question 1

cells are synthesizing new components but no cell growth occurs

Answer 1

lag phase

Question 2

rate of death > rate of growth

Answer 2

death phase

Question 3

rate of death

Answer 3

exponential

Question 4

rate of death = rate of growth

Answer 4

stationary

Question 5

requirements for growth

Answer 5

physical (temperature, pH, osmotic pressure)

chemical (oxygen, carbon, N, S, P, organic growth factor)

Question 6

basis of oxygen sensitivities

Answer 6

oxygen releases free radicles that are toxic when it is reduced

aerobes produce these enzymes (SOD, catalase, peroxidase)

Question 7

mechanisms of control of bacteria

Answer 7

heat
radiation
chemical

Question 8

UV radiation control

Answer 8

causes mutation that creates pyrimidine dimers

Question 9

heat control

Answer 9

denatures proteins

Question 10

phenol

Answer 10

used in acid fast stain (lipid soluble)

denatures proteins + disrupts cell membranes

Question 11

alcohols

Answer 11

disinfect

denature protein, dissolve membrane lipids

Question 12

iodine

Answer 12

oxidizing agents

iodinates proteins

Question 13

chlorine

Answer 13

oxidizing of cell constituents

Question 14

sanitization

Answer 14

reduction of microbial population to level that is safe

Question 15

antisepsis

Answer 15

prevention of infection on living tissue

Question 16

-cidal agents

Answer 16

kill

Question 17

-static agens

Answer 17

inhibit growth

Question 18

heavy metals

Answer 18

combine w/ and inactivate proteins

Question 19

detergents

Answer 19

disrupts membrane

includes soap

Question 20

aldehydes

Answer 20

cross linking agents (proteins, nucleic acids)

Question 21

sterilizing classes

Answer 21

inactivates DNA and proteins