BACTERIAL GROWTH REQUIREMENTS Flashcards
Orderly and organized increase in the sum of all components of the organism
BACTERIAL GROWTH
replication of bacterium into two daughter cells through ____ including structures, organelles and components
binary fission
t or f
Bacteria doesn’t grow in very diverse conditions, which explains why they are not found everywhere
f
certain conditions promote bacterial growth such as ___, ___, __ and __.
temperature, moisture, pH and environmental oxygen.
If thebacteriagrow for six hours, eachbacterium will divide ___ times per hour ×6 hours = 18 times.
3
T OR F
Every time the bacteriareproduce, the number doubles.
T
NUTRIENT REQS OF BACTERIA
Water, carbon source, nitrogen source, inorganic salts, growth factors, sulfur source, phosphorus source
structural backbone of all organic molecules
Carbon
depend on inorganic compounds (C02) as carbon source
autotrophs
depends on organic substances like glucose (CHO)
organotrophs
Growth Factor (growth & development)
Vitamin B complex, amino acid
synthesis of proteins and nucleic acids
Nitrogen, Sulfur Phosphorus
physical reqs of bacteria (please observe him or them, moist and rate)
pH, Osmotic pressure, Hydrostatic pressure, oxygen, temperature, moisture/water, radiation
alkalophiles
8.4-9.0 pH
neutrophiles
6.5-7.5 pH
Acidophiles
less than 6 pH
osmotic pressure determined by _____
salt concentration
high salt concentration
halophiles
high osmotic pressure
osmophiles
(medically important bacteria
Facultative
Thermophiles
higher than 40c
mesophiles
20-40c
psychrophiles
10-20c
Serves as medium for acquiring nutrients
moisture/water
high-energy radiation to sunlight, can be used to kill microbes or inhibit their growth
radiation
represents the number of live cells in abacterialpopulation over a period of time.
bacterial growth curve
There are four distinct phases of the growth curve:
lag phase, logarithmic/exponential phase, stationary phase, death phase
x bacteria are metabolically active but not dividing to synthesize DNA x Attain maximum size at the end of lag phase x Last for 1-4 hours
LAG PHASE
x Rapid cell division x High metabolic activity x Generation time or doubling time x Last for about 8 hours
Logarithmic/Exponential Phase
x Period of equilibrium x Number of living cells equals the # of dead cells. x Growth rate slows down, nutrient depletion x Toxic waste begin to accumulate. x Gram positive become Gram negative
Stationary Phase
x Rapid cell death x Continious depletion of nutrients x Sporulation continues x last for a few hours to a few days
DEATH PHASE
Why does death phase took longer?
because bacterias are hard to eradicate
exponential increase in number of living bacterial cells
log phase
no increase in number of living bacterial cells
lag phase
plateau in number of living bacterial cells; rate of cell division and death roughly equal
stationary phase
exponential decrease in number of living bacterial cells
death or decline phase
