Cultivation, Reproduction And Growth Of Bacteria Flashcards
Growth of bacteria is represented by
Increase in number of cells rather than size
Requirements for growth
Nutritional and physical
Nutritional Requirements for growth
Energy and carbon source Nitrogen Sulfur Phosphorus Potassium magnesium and calcium Trace elements Organic growth factors Water
Phototrophs and chemotrophs
Use solar energy as source of energy
Oxidize chemical compounds for energy
All organisms require a ____ source as it is the structural basis of biochemicals
Carbon
Heterotrophs and autotrophs
Use an organic carbon source
Use CO2 as a carbon source
Four nutritional classes of microorganisms
Chemoautotrophs (chemolithoautotrophs)
Chemoheterotrophs
Photoautotrophs
Phtoheterotrophs
Nitrogen is needed for_____
Obtained:
Protein and nucleic acid synthesis
Obtained via decomposition of proteins or from NH4+ or NO3-
Some bacteria can fix nitrogen
Sulfa is needed to
Sources
Synthesize sulfur contained amino acids and vitamins (thiamine and biotin)
Sources: sulfate ions, hydrogen sulfide, amino acids
Phosphorous is needed
Source
For synthesis of nucleic acids, phospholipids and ATP
Phosphate ions
Potassium, Magnesium and calcium function as
Cofactors for enzymes
Trace elements
Required in small amounts and essential for enzyme activity and act as cofactors usually.
Organic Growth Factors (definition)
Organic compounds essential for the growth of bacterium that cannot be manufactured by the bacterium; must be obtained from the environment
Organic growth factors
Vitamins - (coenzymes) either manufactured or obtained via environment
Amino Acids - needed for protein synthesis
Purines and pyrimidines - needed for nuclei acid synthesis
Water
Nutrients must be in solution with water to be used
Physical conditions required for growth
Temperature
Gaseous atmosphere
pH (Acidity or alkalinity)
Other (osmotic pressure, salinity, light, hydrostatic pressure)
Temperature as a condition for growth
Affects growth, reaction rates and amount of growth. Most bacteria grow within a limited range of temperature
Classification of organisms based on temperature
Psychorphiles
Mesophiles
Thermophiles
Psychrophiles
Cold loving
Mesophiles
Moderate temperature loving microbes
Thermophiles
Heat loving
Optimum growth temperature
Temp in which organism grows most rapidly
Psychotrophs
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Hyperthermophiles
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Obligate aerobes
Use molecular oxygen and produce more energy from nutrients than do microbes that do not use oxygen
Facultative anaerobes
Use molecular oxygen when present but are able to use fermentation or anaerobic respiration when free oxygen is not available