PRELIM 02 - Microbial Growth and its Control Flashcards
__________ increase in number not size
Microbial growth
Time required for a cell to divide and its population to double
Generation time
Temperature (Type of requirement for microbial growth)
Physical
pH (Type of requirement for microbial growth)
Physical
Osmotic pressure (Type of requirement for microbial growth)
Physical
Carbon (Type of requirement for microbial growth)
Chemical
Nitrogen, Sulfur, Phosphorus (Type of requirement for microbial growth)
Chemical
Trace elements (Type of requirement for microbial growth)
Chemical
Oxygen (Type of requirement for microbial growth)
Chemical
Organic growth factors (Type of requirement for microbial growth)
Chemical
pH of most bacteria
6.5-7.5
pH of acidophiles
1
pH of fungi
5-6
Organisms that can grow at high salt concentrations
Extreme halophiles
High osmotic pressure (hypertonic) results to __________
Plasmolysis (shrinkage)
Low osmotic pressure (hypotonic) results to __________
Swelling
The structural backbone of living matter; it is half the dry weight of bacterial cell
Carbon
2 types of carbon sources
Chemoheterotrophs, Chemoautotrophs & photoautotrophs
A type of carbon source that get carbon from organism materials such as proteins, carbohydrates, and lipids
Chemoheterotrophs
A type of carbon source that get carbon from carbon dioxide
Chemoautotrophs & photoautotrophs
3 elements needed in the synthesis of biomolecules
Nitrogen, Sulfur, Phosphorus
Elements required in small amounts and are usually needed as cofactors
Trace elements
4 examples of trace elements
Fe, Cu, Mo, Zn
Are essential organic compounds which includes vitamins, amino acids, pyrimidines, and purines
Organic growth factors
A thin, slimy layer encasing bacteria that adheres to a surface
Biofilm
A complex polymer containing many times its dry weight in water
Hydrogel
A microorganism that form biofilms on teeth and gums, contributing to dental plaque and dental caries
Streptococcus mutans
Destruction or removal of all forms of microbial life, including endospores but with the possible exception of prions
Sterilization
Sufficient heat treatment to kill endospores of Clostridium botulinum in canned food
Commercial sterilization
Destruction of vegetative pathogens on inanimate objects
Disinfection
Destruction of vegetative pathogens on living tissue
Antisepsis
Removal of microbes from a limited area, such as the skin around an injection site
Degerming
Treatment is intended to lower microbial counts on eating and drinking utensils to safe public health levels
Sanitization
Chemical that kills microorganisms
Biocide/Germicide
Inhibits the growth and multiplication of bacteria
Static
State of bacterial contamination
Sepsis
State of absence of contamination
Asepsis
Practices that exclude all organisms from contaminating media or contacting living tissues
Aseptic technique
2 methods used in control of microbial growth
Physical, Chemical
4 phases of microbial growth
Lag, Log, Stationary, Death
Intense activity preparing for population growth, but no increase in population (Phases of microbial growth)
Lag phase
Logarithmic or exponential increase in population (Phases of microbial growth)
Log phase
Period of equilibrium; microbial deaths balance production of new cells (Phases of microbial growth)
Stationary phase
Population is decreasing at a logarithmic rate (Phases of microbial growth)
Death phase
Only aerobic growth; oxygen is required (Type of microbe according to oxygen requirement)
Obligate aerobes
Both aerobic and anaerobic growth; greater growth in the presence of oxygen (Type of microbe according to oxygen requirement)
Facultative anaerobes
Only anaerobic growth; growth ceases in the presence of oxygen
Obligate anaerobes
Only anaerobic growth; but growth continues in the presence of oxygen
Aerotolerant anaerobes
Only aerobic growth; oxygen required in low concentration
Microaerophiles
