Microbial Growth

environmental factors that affect growth and survival rate

atmospheric gases, temp, pH, radiation, osmotic pressure, avail to nutrients

environmental factors that affect the function of metabolic enzymes

high temp and low pH, enzymes are proteins so these factories disrupt their protein structures making them unable to function

environmental lab condition factors that are affect microbial growth

incubators with optimal growth temp., anaerobe jar, refrigerator and freezers

Fluid thioglycollate medium

liquid medium used to support growth of aerobic and anaerobic organisms. has indicator pink when o2 is present in median container, small agar to localize organisms, yellow low o2, white not o2,

obligated aerobes

grow on surface of FTM where o2 is high, O2 to grow, cloudy on top?

obligate anaerobes

will only grow deep in the bottom of FTM tube where oxygen is absent, cloudy near the bottom, must be grown in anaerobic jar

facultative anaerobes

grow throughout FTM tube, appears cloudy throughout because they can grow in anaerobic and aerobic conditions

microaeophiles

small thing band near but not at top

anaerobe jar

oxygen free environment, chemical catalyze run activated to remove free oxygen and indicator strip verifies anaerobic conditions inside

cardinal temps a microbe can survive

optimum, minimum, maximum

optimum

small range of temp in which microbe experience fastest rate of metabolism and growth

min and max

temps extreme boundaries for the survival of an organusm

below minimum temp

organisms metabolic activities are inhibited, mem loses fluidity for transport and growth, cannot continue until temp rises

above maximum temp

irreversible renature of an organisms enzymes occurs and results in death

turbidity

none= no growth, slight = some growth, very = high growth, reliant on temp.

temp can affect growth and phenotype, Serratia Martens

at 25C re protein pigement agross small part, 38C cannot produce this pigment

acid pH level

<7

alkaline

7<

if pH levels are outside of organisms survival range

proteins can denature and result in cell death

isotonic

equal solute concentration to cell, water moves in and out at similar rates, no change in cell volume

hypotonic

lower solute concentration than cell, water moves into cell

hypertonic

higher solute concentration, water leaves cell, bacterial mem will shrink