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MOLB Chapter 6
Microbial Growth
Question | Answer |
---|---|
Carbon | heterotrophs/autotrophs are carbon fixing |
Nitrogen | need for amino acids and nucleic acids, by breaking down amino acids from the environment(ammonia, nitrate) |
Sulfur | protein, vitamins, break down amino acids, absorb sulfate/hydrogen sulfur from the environment |
Phosphorus | nucleic acids, membranes, ATP, absorb phosphate groups |
optimal pH for bacteria | 6.5-7.5 |
optimal pH for mold/yeast | 5-6 |
Complex media | have an unknown concentration of nutrients |
Defined media | know the exact concentration of nutrients |
Differential Media | media that allow identifiable reactions MSA agar |
Selective Media | suppress the growth of unwanted organisms while promoting growth of desired organism, EMB |
Enrichment media | used to increase small amounts of an organism to a detectable level, phenol added to media |
Agar | used as a solidifying agent for culture media, generally not metabolized by microbes, liquefies as 100, solidifies at 40 |
Lag Phase | prepares for population growth, no growth |
log phase | exponential increase in population |
Stationary Phase | cell death equals increase in population |
Death Phase | population decreases at a logrhithmic rate |
BSL I | no special precautions |
BSL II | lab coat, gloves, eye protection |
BSL III | biosafety cabinets to prevent airborne transmission |
BSL IV | sealed, negative pressure, exhaust air is filtered twice |