2 - Bacterial Growth and Nutrition Flashcards
Substances used in biosynthesis of cellular components and energy production
Nutrients
gm/L of culture medium
Macroelements
most important chemical requirement, next to water
Carbon
required for skeleton or backbone of all organic molecules
Carbon
50% of phospholipid layer of cell membrane (dry weight)
Carbon
Obtain carbon by recycling process (breakdown of pre-existing molecules to produce new substances):
Chemoheterotrophs
Obtain carbon by production from CO2
Chemoautotrophs (pathogenic bacteria)
14% of phospholipid layer of cell membrane (dry weight)
Nitrogen
Essential part of amino acids that together form proteins for cellular tasks
Nitrogen
End products of all pathways for nitrogen assimilation
Ammonia (NH3)
use of atmospheric or gaseous N for cell synthesis
Nitrogen fixation
Nitrogen is obtained from (3)
- Nitrogen fixation
- Decomposition of nitrogen-containing compounds
- Ammonium ions
How does available NH3 diffuse into the bacterial transmembrane channels?
As GASEOUS NH3 rather than ionic ammonium (NH4+)
Major element in all organic compounds and several inorganic ones
Hydrogen
Maintains pH, forms H bonds in macromolecules
Hydrogen
Acts as prime force in oxidation-reduction reactions of respiration
Hydrogen
8% of phospholipid layer of cell membrane (dry weight)
Hydrogen
Source of free energy in redox reactions
Hydrogen
plays an important role in structural and enzymatic functions of the cell
oxygen
Electron acceptor in anaerobic respiration
Oxygen
Makes up approximately 20% of the atmosphere
Oxygen
20% of phospholipid layer of cell membrane (dry weight)
Oxygen
Major component of carbohydrates, lipids and proteins
Oxygen
How is Sulfur produced or obtained?
As SO4- (superscript) and H2S (subscript)
For biosynthesis of amino acids (cysteine, cystine, methionine) and vitamins (thiamine and biotin)
Sulfur
Protein structure (for linkages called disulfide bonds)
Sulfur
Essential for synthesis of nucleic acids and ATP
Phosphorus
Main form of phosphorus and where is it derived?
phosphate; H3PO4
Measured in mg/L in culture medium
Microelements
What are the Macroelements?
CHONSP
What are the Microelements?
CaFe MgK
Exist in nature as cations
microelements
Contributes to heat resistance and bacterial endospore formation
Calcium
Constituent of gram positive cell wall
Calcium
Part of cytochromes and a co-factor for enzymes and electron-carrying capacity
Iron
Uptake of iron in bacteria ismediated by? This acts to chelate iron and transport it.
Siderophore
stabilizes ribosomes and cell membranes
magnesium
Serves as cofactor for enzymes, complexes with ATP
Magnesium
Protein synthesis and membrane function (function and integrity of ribosomes)
Potassium
Measured in ug/L
Trace Elements
When trace elements are in excess, they are termed ____ because of their toxicity.
Contaminants
Essential for catalysis of reactions and activation of enzymes as co-factors
Trace elements
What are the Trace Elements?
ZiCuCOMnMoNi
Zinc, Copper, Cobalt, Manganese, Molybdenum, Nickel
Organic compounds required because they are essential cell components or precursors of such component and cannot be synthesized by the organism
Growth Factors
3 classes of growth factors
Amino acids
Purines and pyrimidines
Vitamins
make up all or part of enzyme co-factors and only very small amounts sustain growth
Vitamins
Growth factor for protein synthesis
Amino acids
Growth factor for nucleic acid synthesis
Purines and pyrimidines
ATP source of chemoautotrophs (lithoautotrophs)
Inorganic compounds
Carbon source of chemoautotrophs (lithoautotrophs)
CO2
ATP source of chemoheterotrophs
Organic compounds
Carbon source of chemoheterotrophs
Organic compounds
ATP source of photoautotrophs and photoheterotrophs
Light
Carbon source of photoautotrophs
CO2
Carbon source of photoheterotrophs
CO2
5 physical requirements of bacteria
TAPOH
Temperature, atmosphere, pH, osmotic pressure, hydrostatic pressure
True or False. Temperature affects the type of reproduction of a bacteria.
True
True or False. All processes of growth are dependent on chemical reaction that are affected by temperature
True
At the most favourable temperatures for growth, the number of cell divisions per hour (growth rate) generally ____ for every increase of __°C
doubles; 10
Temp at which it grows best (fastest rate of growth and metabolism)
Optimum temperature
Temp at which enzymatic reactions are occurring at maximal possible rate
Optimum temperature
Temp at which there is membrane gelling; transport processes are so slow that growth cannot occur
Minimum temperature
Temp at which there is protein denaturation and thermal lysis
Maximal temperature
Found in colder waters and soil (deep ocean, polar regions, arctic environment) at 0 – 15°C
Psychrophiles
Thrive at temperature of 15 – 20°C
Psychrotrophs
At refrigerator temperature (4-10°C) they spoil food stored for prolonged periods
Psychrotrophs
3 forms of spoilage
- Mold mycelium
- Slime on food surface
- Off taste/off color
Thrive at 25 - 40C
Mesophiles
Optimal temp for free living mesophiles
30C
Optimal temp for pathogenic organisms
37C
Upper part mesophiles
Parasitic organisms
saprophytic bacteria, fungi, algae and protozoa
Lower part mesophiles
Thrive best at 40 - 85C
Thermophiles
Found in volcanic areas, compost heaps, hot springs
Thermophiles
Most thermophiles are?
Prokaryotes
Thrive best at temp greater than 80C
Hyperthermophiles
Hyperthermophiles are under?
Archae