MICROBIAL GROWTH PHASES I

Question 1

time it takes for a single cell to go from one division to next

Answer 1

generation time/doubling time

Question 2

how bacterial population increases

Answer 2

exponentially/logarithmically

Question 3

where organisms are “getting used to the medium and physical conditions

Answer 3

lag phase

Question 4

this is the phase where the generation time is measured.

Answer 4

log phase

Question 5

during this phase, the number of new cells equals the number of dead cells.

Answer 5

stationary phase

Question 6

rate of cell death is faster than regeneration.

Answer 6

death phase

Question 7

GENERAL MICROBIAL GROWTH CONTROL with meaning

Answer 7

sterilization - complete destruction
commercial sterilization - heat treatment
disinfection - inanimate surfaces
antisepsis - living tissue
degerming - mechanical removal
sanitation - lower microbial counts
antibiotic - agent, kills other microorganisms

Question 7

MICROBIAL GROWTH PHASES:

Answer 7

lag phase
log phase
stationary phase
death phase

Question 8

types of HEAT:

Answer 8

moist heat
pasterization
tindallization
dry heat

Question 9

PHYSICAL METHODS OF MICROBIAL CONTROL

Answer 9

heat
filtration
cold
high pressure
desiccation
osmotic pressure
radiation

Question 10

types of dry heat and the 3 parameters:

Answer 10

hot air oven
direct flaming
incineration
THERMAL DEATH POINT
THERMAL DEATH TIME
DECIMAL REDUCTION TIME

Question 11

physical separation of bacteria from suspending liquid

Answer 11

filtration

Question 12

this type of air filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (µm).

Answer 12

HEPA (high efficiency particulate air filter)

Question 13

decreases chemical reactions and possible changes in protein

Answer 13

cold

Question 14

types of COLD with meanings

Answer 14

refrigeration - slows down
deep-freezing - dormant stage
lyophilization - long term preservation

Question 15

alteration of molecular structure of proteins and carbohydrates

Answer 15

high pressure

Question 16

used in food preservation which involves in removal of water form microbes

Answer 16

desiccation

Question 17

X-rays and gamma rays easily penetrate paper and plastic and can therefore be used to sterilize many packaged materials

Answer 17

radiation

Question 18

results in loss of water from microbial cells

Answer 18

osmotic pressure

Question 19

types of radiation with meaning

Answer 19

ionizing - destruction of bacteria’s DNA
non-ionizing - damaging of bacteria’s DNA

Question 20

types of non-ionizing

Answer 20

infrared radiation - cause of oxidation
UV radiations from pyrimidine dimers - prevent DNA replication