Chapter 4

Question 1

• Orderly increase in the sum of all the
  components of an organism
• Cell multiplication, increase in the number of
  single bacteria making up population , “culture”

Answer 1

growth

Question 2

the number of viable cells per unit volume of
culture

Answer 2

cell concentration

Question 3

dry weight of cells per
unit volume of culture

Answer 3

biomass concentration

Question 4

• Can be measured by cell concentration (the
  number of viable cells per unit volume of
  culture)
• Biomass concentration (dry weight of cells per unit volume of culture)

Answer 4

Viable cell count

Question 5

• Measured by photoelectric means
• Related to viable count using a standard curve
  -A barely turbid suspension of Escherichia coli
  contains about 107 cells per milliliter, and a
  fairly turbid suspension contains about 108 cells per milliliter

Answer 5

turbidity

Question 6

 The Growth Rate Constant
 Can be measured in grams of biomass producedper hour
 Product of time (t)
 Growth rate constant (k)
 Biomass concentration (B)

Answer 6

Exponential growth

Question 7

Increase in cell number, not cell size!

Answer 7

microbial growth

Question 8

what are the physical requirements for growth: Temperature

Answer 8

minimum growth temperature, optimum growth temperature, maximum growth temperature

Question 9

Five groups based on optimum growth
temperature

Answer 9

1. Psychrophiles
2. Psychrotrophs
3. Mesophiles
4. Thermophiles
5. Hyperthermophiles

Question 10

– period of little or no cell division and it
can last for 1 hour or several days

Answer 10

Lag

Question 11

cells begin to divide and enter a period
of growth or logarithmic increase; cells are
most active metabolically

Answer 11

log

Question 12

metabolic activities of
individual surviving cells slow; microbial death
balance the no. of new cells; period of
equilibrium

Answer 12

stationary

Question 13

no. of death exceeds the no. of new
cells formed

Answer 13

death

Question 14

• Death mean irreversible loss
   If it fails to give rise to a colony
   Depends on the medium
   First hour after treatment are also critical in the determination of “killing.”

Answer 14

measurement of death

Question 15

physical methods for bacterial control of microbial growth

Answer 15

 sterilization
 Disinfection
 Pasteurization
 aseptic technique

Question 16

Some Common biocides used for Antisepsis, Disinfection, Preservation and other purposes

Answer 16

alcohols, aldehydes, Biguanides, Bisphenols, Halogen-releasing agent, heavy metal derivatives, organic acids, peroxygens, phenols and cresol, quaternary ammonium compounds, vapor phase

Question 17

Strategies to Control Bacteria at the Environmental Level

Answer 17

 Antibiotics as the gold standard of treatment
 Prevent exposure to infectious agents

Question 18

destroys or eliminate all forms of microbial life from an object or environment

Answer 18

sterilization

Question 19

eliminates many or all pathogenic microorganisms, except bacterial spores from an object or an environment

Answer 19

disinfection

Question 20

application of heat, for the purpose of killing or retarding the development of pathogenic bacteria

Answer 20

pasteurization

Question 21

pathogenic organisms are reduced to safe levels on in animate object, reducing cross infection

Answer 21

sanitization

Question 22

removal of organic or inorganic material from objects and surfaces, manually or mechanically using water with detergent or enzymatic product

Answer 22

cleaning

Question 23

chemical or physical agent usually broad spectrum that inactivates microorganisms

Answer 23

biocide

Question 24

• term to a property by which biocide is able to kill bacteria
• Killed organism can no longer reproduce even after being removed from contact with the agent
• causes lysis (dissolution) of the cells

Answer 24

bacteriocidal

Question 25

• the property by which a
  biocide is able to inhibit bacterial multiplication
   Upon removal of the agent multiplication
  resumes
   fungistatic and sporostatic

Answer 25

bacteriostatic

Question 26

presence of pathogenic microbes in
living tissues

Answer 26

septic

Question 27

free of, using method to free of
microorganism

Answer 27

aseptic

Question 28

– agents that destroy or inhibit the
growth of microorganism in or on living tissues

Answer 28

antiseptic

Question 29

substance added to food
products or to an organic solution to prevent
chemical change or bacterial action

Answer 29

preservative

Question 30

• substance that interferes with a
  particular metabolism
   Bactericidal or bacteriostatic

Answer 30

antibiotics

Question 31

General Mechanism of Biocide Action

Answer 31

 Disruption of the Cell membrane or wall
 Protein Denaturation
 Disruption of Free Sulfhydryl Groups
 Damage to DNA
 Chemical Antagonism
 Physical Methods

Question 32

simplest means of sterilizing materials
bactericidal and sporicidal if performed
appropriately

Answer 32

heat

Question 33

bactericidal but not sporicidal

Answer 33

radiation

Question 34

used of biochemical agents

Answer 34

chemical agents

Question 35

liquid desiccants, bactericidal but
not sporicidal

Answer 35

alcohols

Question 36

disinfection and sterilization of
instruments, endoscopes and surgical tools. Bactericidal and sporicidal

Answer 36

aldehydes

Question 37

used in hand washing and oral
products, disinfectant and preservative, bactericidal but not sporicidal

Answer 37

biguanides

Question 38

used in antiseptic soaps and hand
rinses, bactericidal and sporostatic (not
sporicidal)

Answer 38

bisphenols

Question 39

Releasing agents – destroys cellular
activity of proteins, sporicidal if high
concentration

Answer 39

halogen

Question 40

used of combination of two antibacterial agents, not sporicidal

Answer 40

heavy metal derivatives

Question 41

preservative in pharmaceutical and food industries, neither sporicidal

Answer 41

organic acids

Question 42

– requires high concentration to be bactericidal and sporicidal

Answer 42

peroxygens

Question 43

have antiseptic, disinfectant or preservative properties, not sporicidal

Answer 43

phenols

Question 44

used in variety of clinical purposes, not sporicidal

Answer 44

quaternary ammonium compounds

Question 45

sterilized heat sensitive medical devices, sporicidal

Answer 45

vapor-phase sterillants