Bacterial Growth -Chapter 3 Flashcards
Doubling time/growth rate + understand under different conditions (nutrient metabolism )
- bacterial growth will depended on ideal conditions
- stable environment= K-selection vs. unstable envi.=r-selection (leads to adaptive change)
Compare and contrast the growth in pure cultures with growth in the environments
dependent on physical and chemical properties:
- limited nutrients status
- microoganisms present, nutrient competition
- predation
Growth curve and the parts of the curve under both the lab and environement
- Lag
- exponential : rate of icnrease proportional to thee number of cellls, low initial cell number= initial growth rate
- stationary phase
- death phase
Batch vs. Continuous cultures (how to generate primary or secondary metabolites)
ie. plate vs. add nutrients/remove waste
-low [substrate ]= batch
vs.
-optimal growth
-control flow, [substrate]. pH, temp, O2 levels, ect.
-removes effluent (contains cells, metabolites, waste, unused nutrient)
-controls growth rate (dilution rate/inflow, influent substrate) : control 1 met (high flow), 2 met (low flow)
Different types of bacteria with respect to growth rate
- oligotrophs (K strategist, prefer low [sub ], low+consistent response, slow metabolism/cell maintenance)
- copiotrophs ( r strategist, prefer high [sub], rapid response, fast metabolism/exponential growth or dormant stat)
At least two electron acceptors can be used under anaerobic condition in place of oxygen
sulfate/So4^-2
nitrate/No3^-1
Sulfur /S
Aerobic or anaerobic metabolism yields more energy + why?
Aerobic yields more + uses C for cells mass orCO2 only
- in anerobic /fermentation they use dif e- acceptor–> will use the highest electron affinity first, (final step) when e- acceptors DEPLETED= methanogenesis
- Anaerobic –> disproportionation ( some C –> Co2=Ei acceptors and others CH4
Mass balance equation for aerobic and anerobic metabolism
-anerobic resp =LESS efficient, requires alternative e-
Taxonomic units
a population, or group of populations of organisms which are usually inferred to be phylogenetically related and which have characters in common which differentiate the unit (e.g. a genus, a family, an order) from other such units (Woese)
Cell yield coefficient (y)
the unit amount of cell mass produced per unit amount of substrate consumed
What’s happening during the stationary phase?
- growth=death
- bac deal w/ competition
- growth is balanced
Why do we use the terms substrate and nutrient?
substrate= E or carbon source, metabolisms ie. oil nutrient= required for growth and repair ie. Nitrogen
Why do we use the terms substrate and nutrient?
substrate= E or carbon source, metabolisms ie. oil nutrient= required for growth and repair ie. Nitrogen
Give an example of efficiency of degradation of a substrate and how we use this?
-increase effiency= increase yield coefficient
Oligotrophy
poor nutrient
growth rate stays constant
What would the addition of substrate to their environments result in for r and K strategists?
r= increased growth
k=no growth
Why are you more likely to find dormant copiotrophic organisms?
they dont control consumption therefore use of nutrients up ==> dormant
Why would oligotrophs be difficult to culture in the laboratory?
- long time needed and often becomes contaminated
- need to know particular nutrient needs
How might we be able to study oligotrophic growth?
- use chemoreactor
- acteria rely on the metabolites from another bac ( SYMTROPHY)
Why do we need to be careful when attempting to culture and identify soil microorganisms in a lab?
- symtrophy
- ongoing flu of bacterial population in the env. which can alter the growth of other present bacd
In a pharmaceutical setting, especially in the production of injectables, it is critical to verify that there are no microorganisms present, how would you show whether there are microorganisms present? (Can you be certain that certain microorganisms don’t exist?)
- VBDC
- 16 s sequencing (help o id
In a pharmaceutical setting, especially in the production of injectables, it is critical to verify that there are no microorganisms present, how would you show whether there are microorganisms present? (Can you be certain that certain microorganisms don’t exist?)
- VBDC
- 16 s sequencing (help to identify)
- look for metabolites or toxins/endotoxins
What might occur to remedy the situation where the correct microbe is not present in the environment?
microbes adapts to fit environment
What may happen to the oligotrophic population when substrate is added?
copiotrophic pop may become overwhelming and or use up nutrients or O2
What do values for Y indicate about compounds as substrates for bacterial growth?
the cells must contain catabolic pathways to utilize a specific substrate for growth
What do values for Y indicate about compounds as substrates for bacterial growth?
the cells must contain catabolic pathways to utilize a specific substrate for growth
How can you change the growth rate under ideal nonlimiting conditions?
change temps
- if you want to change growth rate= change microbe or substrate
Describe the process a facultative microorganisms would use to metabolize a substrate?
- they rely on fermentation and in turn methanogensis.
- they utitlize C to create cell mass and also disproportionanation ( Co2 and CH4)
What does redox potential mean?
the measure of the tendencies of a chemical species to acquire e- and in turn be reduced
What is a redox pair?
e- donor (Cu+) and e- acceptor (Cu2+)
How do we measure energy produced during metabolism?
- calculate the delta Eo` ( free energy)
- quantify the products produced
Which type of substrate is likely to give most energy, a highly oxidized or a highly reduced substrate?
*transfer of e-
highly reduced
How is nitrate reductase expression regulated?
kept within a balance,
- relative rates of synthesis and activation or degredation and inactivation
Why is regulation by nitrate important?
nitrate reducate is important in the assimilation of exogenous nitrogen –> fixed nitrogen
Where might you find expression of nitrate reductase?
- in plants and in other nitrogen fixating bac
Critical dilution rate
- amount of diltuion (amount of nutrient/substrate in solution) being introduced so that the GROWTH RATE =0
- leads to washout
