Ziegler- Bacterial Growth Flashcards
What is bacterial replication?
The generation of 2 complete daughter cells from 1 cell.
What do bacteria use to multiply?
Binary fission
What are the steps of binary fission?
- Replication of DNA
- Polar separation of daughter chromosomes
- Generation of cross wall
- Separation
What is generation time?
- The time it takes for ONE cell to become TWO (also the amount of time required for a number of cells in culture to DOUBLE)
The doubling time is equal to….
the generation time!
What are other characteristics of bacterial growth?
- Descendants are Clones
- Asynchronous replication
- Cell numbers are measured by concentration or biomass
What is the growth curve?
- A saturated broth culture is used to inoculate fresh media
- Bacterial counts are taken at different time points and plotted as cell number versus time
What is the lag phase?
The time it takes for bacteria to ADAPT to a new nutrient rich environment.
What is the log phase?
- Exponential growth!–New cell material is synthesized at a constant rate.
- Bacteria double every generation time
What is the stationary phase?
- Nutrients are exhausted
- toxins products build up
- bacteria remain at constant number
What is the death phase?
- Bacteria die because of toxicity
Not all bacteria have this
What is a bacterial colony?
Tens of millions of individual bacteria from a single organism.
How do you determine the concentration of bacteria in liquid culture?
- Dilute it
- Plate it (onto media/nutrients that bacteria needs to grow)
- Each colony represents ONE bacterium from the original culture.
What do you do for a given culture at each time point?
- Make a 10 fold dilutions of a culture
- Spread known volume on agar plate
- Allow colonies to grow
- Count the number of colonies
- Calculate original concentration (at time of sampling)
**REPRESENTS VIABLE BACTERIA
What are the growth requirements for bacterial cultivation?
- Elements for organic matter (CARBON SOURCE)
2. Ions for energy generation, catalysis and osmostic maintenance.
What are the energy sources for bacterial cultivation?
FRP
- Fermentation–formation of ATP not couple to e transfer
- Respiration–formation of ATP by oxidative phosphorylation, ATP formed during e transfer
- Photosynthesis– ATP formed by reduction of an oxidant via light energy. (NO BACTERIA USE THIS)