cell growth 10/1 Flashcards
what does growth in an open system allow for
–continual provision of nutrients
–continual removal of wastes and cells
what does the continuous culture of microorganisms allow for and how is done
- Maintains cells in log phase at a constant biomass concentration for extended periods
- Achieved using a continuous culture system
what are important aspects of continuous culture methods
- Study of microbial growth at very low nutrient concentrations, close to those present in natural environment
- Study of interactions of microbes under conditions resembling those in aquatic environments
- Food and industrial microbiology
what is the chemostat
- Device for continuous culture in lab
- Rate of incoming medium = rate of removal of medium from vessel (with wastes and cells)
- An essential nutrient is in limiting quantities
what type of environment do most microorganisms grow in
fairly moderate
what are extremophiles
–grow under harsh conditions that would kill most other organisms
what is hypotonic solution
–(lower osmotic concentration) – cells are hypertonic
- water enters the cell
- cell swells may burst
what is hypertonic solution
–(higher osmotic concentration) – cells are hypotonic
- water leaves the cell
- membrane shrinks from the cell wall (plasmolysis) may occur
why and how would a cell reduce osmotic concentration of the cytoplasm in hypotonic solution
•if cell too hypertonic
–mechanosensitive (MS) channels in plasma membrane allow solutes to leave by diffusion
how and why would a cell increase osmotic concentration of cytoplasm in hypertonic solution
•(if cell too hypotonic)
–synthesize solutes compatible with metabolism and growth
–pump in ions
at which osmotic concentration to most cells try to stay at
slightly hypertonic to the environment
