Microbial Population Growth Flashcards
What domains are microorganisms found in?
All 3 domains but primarily within the prokaryotes (bacteria and archaea)
what is the dominant life form?
Prokaryotes
How many bacterial cells estimated to be on earth?
5x10^30
What is most life?
Microbial
Are microorganism pathogenic?
Only a very small fraction
Why are prokaryotes so dominant?
Because they are small which means they have a fast growth rate and can therefore evolve and adapt fast
What is binary fission?
The cell division process which prokaryotes use to reproduce asexually. 1 cell to 2
What is the result of binary fission?
Two cells that are genetically identical
What is the first step of binary fission?
Chromosome replication begins
What happens after chromosome replication begins?
One copy of the origin is now at each end of the cell
What happens once one copy of the origin is at each end of the cell?
Replication finishes
What does closed batch culture system refer to?
A form of cell culturing
What is within a closed batch culture system?
There is a defined amount of nutrient supply provided and once used, the cells can’t multiply (there is no in flow or out flow of nutrients)
what is closed batch culture system?
The standard method of studying microorganisms in culture
What is closed batch culture system dictated by?
The method, not the shape of the flask
What is the lag phase?
The time between when an organism is first put in the conditions to when biosynthetic reactions begin (growth starts)
What does the length of the lag phase depend on?
The history of the organism (whether it has come from same, similar or different conditions)
What is the exponential phase?
When cells are actively dividing and nothing is limiting for growth. Population will double in a constant time interval under standard conditions
What is stationary phase?
When cells stop growing and cryptic growth is observed
What is cryptic growth?
When organisms survive by consuming lysed cell constituents of other dead cells within the culture. It is not a static population but a dynamic population
What is meant by a dynamic population?
There is an equilibrium between the death rate and growth rate
What is death phase?
Cell death. Equilibrium between growing cells and dying cells is skewed to the dead
What does batch culture analysis measure?
The average behaviour of cells
What is penicillin?
An antibiotic which kills bacteria by blocking cell wall synthesis, only growing/replicating bacteria are affected
Why are persisters insensitive to penicillin?
because they are in a dormant, non-dividing phase, similar to that of bacteria in the lag phase of the growth curve, and because penicillin kills bacteria only when they are dividing or about to divide
What do prokaryotes need to multiply?
Carbon source, energy source and reducing power
What is carbon source?
Building blocks needed for macromolecular synthesis
What is energy source?
(Electrons) to drive anabolic and catabolic reactions in a cell
What is reducing power?
Carriers of energy/electrons (NAD+/NADP+) for transferring energy
How do prokaryotes harvest energy?
From chemical energy stored in bonds. Broken chemical bonds release energy that can be captured in new bonds (ATP)
What is the most common energy currency?
ATP
What can be done with ATP bonds formed?
The can be broken again later to release the energy
What is catabolism?
Energy generation “energy/building block harvesting”
What happens during catabolism?
The breakdown of food into products
What is anabolism?
Energy consumption “energy/building block use”
What happens during anabolism?
Monomers are built up into macromolecules and other cellular constituents
What is the two possible energy sources?
Chemical compounds and light
What is the prefix if the energy source is light?
Photo-
What is the prefix if the energy source is chemical compounds?
Chemo-
What are the two possible carbon sources?
Carbon dioxide and organic compounds
What is the prefix if the carbon source is carbon dioxide?
Auto-
What is the prefix if the carbon source is organic compounds?
Hetero-
What processes may chemoheterotrophs undergo?
aerobic respiration, anaerobic respiration or fermentation to get energy
