Microbial population growth Flashcards
Describe basic structure of a prokaryotic cell
DNA - no nucleus. Membrane.
No organelles
What composes a prokaryote
Protein. RNA. Lipid. Saccharide. DNA. Inorganic ion (in decreasing amounts)
Microorganisms and life
Prokaryotes ae most dominant life form (5 nonillion). Only very small fraction are pathogenic
Why are prokaryotes dominant
They have a fast growth rate (reproduce every 15 mins) and therefore are fast to adapt/evolve
What is binary fission
Asexual reproduction of prokaryotes through cell division to produce two genetically identical cells
Describe a closed batch culture system
Form of cell culturing. Set amount of nutrients, nothing in or out. Once used cells cannot proliferate (multiply)
What are the 4 stages of microbial growth (in closed batch)
1 - Lag phase
2 - Log phase (exponential)
3 - Stationary phase
4 - Death phase
Describe lag phase
Time required to get biosynthetic reactions running
Describe log (exponential) phase
When cells are actively dividing. Population doubling in constant time intervals (ideal conditions)
Describe stationary phase
Dynamic population - equilibrium of growing and dying cells.
Cryptic growth observed - consuming lysed cell from dead cells
describe death phase
Equilibrium skewed towards death
What are persistent bacteria
Insensitive to penicillin as they are dormant. Penicillin only kills bacteria actively dividing.
What do prokaryotes need to multiply
carbon - building block for macromolecule synthesis
Energy - (electrons) to drive anabolic and catabolic reactions
Reducing power - Energy carriers (NAD+/NADP+)
How do prokaryotes harvest energy
When bonds broken chemical energy stored is released and captured in ATP bonds
Describe photoautotrophs
Get energy from light.
Get simple carbon to from complex carbon.
Can sustain themselves
