Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
29 Cards in this Set
- Front
- Back
Microbial growth
|
Increase # of cells not size
|
|
Requirements for growth
|
Physical- Temp, pH, Osmotic Pressure
Chemical- sources of carbon, nitrogen , sulfur, phosphorus, trace elements, oxygen , and organic factors. |
|
Psychrophiles Pref Temp
|
min -10 max 30 optimal 15 degrees C
|
|
Mesophiles pref temp
|
min 10 max 50 optimal 37
|
|
Thermophiles pref temp
|
min 40 max 70 optimal 60
|
|
Hyperthermophiles pref temp
|
min 70 max 110 optimal 95
|
|
pH mold yeast acido philes
|
Most bacteria grow 6.5 -7.5
Molds and yeasts grow 5-6 Acidophiles grow only in acidic enviro |
|
Osmotic pressure
|
Hypertonic environments, increased salt or sugar cause plasmolysis
-cell wall protects bacteria from hypotonic enviro -extreme or obligate halophiles require high osmotic pressure facultative halophiles tolerate high osmotic pressure |
|
Carbon
|
-structural organic molecules energy source
-heterotrophs use organic carbon sources -autotrophs use CO2 |
|
Nitrogen
|
-in amino acids, proteins
-most bacteria decompose proteins -some bacteria use NH4+ or NO3- -a few bacteria use n2 in nitrogen fixation |
|
Sulfur
|
-in amino acids and biotin
-most bacteria decompose proteins -some bacteria use SO4^2- or H2S |
|
Phosphorus
|
-In DNA RNA ATP and membranes
PO4^3- is a source of phosphorus |
|
Trace elements
|
Inorganic elements required small amounts
-potassium, magnesium,calcium, iron, copper, zinc Usually as enzyme cofactors |
|
Organic Growth factors
|
organic compounds obtaines from the environment
vitamins, amino acids, purines, pyrimidines |
|
Culture Media
|
Nutrients prepared for microbial growth in the lab
|
|
Sterile
|
No living microbes
|
|
Inoculum
|
Introduction of microbes into medium
|
|
Culture
|
Microbes growing in on culture medium
|
|
Culture medium
|
liquid for = broth solid gel form using agar = plates slants and deeps
|
|
Agar
|
Complex poly saccharide
used as solidifying agent for culture media in petri plates slants and deeps generally not metabolized by microbes l |
|
Selective media
|
suppress unwanted microbes and encourage desired microbes.
|
|
Differential media
|
make it easy to distinguish colonies of different microbes
|
|
Reproduction Prokaryotes
|
Binary fission
Cell elongates and DNA is replicated Cell wall and plasma membrane begin to divide Cross wall forms completely around divided DNA Cells separate |
|
Phases of bacterial growth in a new culture
Lag Phase |
initial period of little to no cell division
|
|
log phase
|
period of exponential growth with a constant generation
|
|
Stationary Phase
|
cell GROWTH IS EQUAL TO CELL DEATH
|
|
Death Phase
|
Cell death exceeds cell growth
|
|
Quantifying microbial growth -Direct measurements
|
Plate counts filtration most probable number direct microscopic count
|
|
Indirect Estimations
|
Turbidity metabolic activity dry weight
|