Bacterial Cultures Flashcards
1
Q
Closed Culture
A
-Bacteria is added to medium and allowed to grow
-Nothing is added or taken away
-“batch culture”
(this is what we use)
2
Q
Open Culture
A
- Materials may be added or subtracted during growth
- Medium is always renewed, so dead cells are removed and new nutrients are added
- Culture keeps growing continuously
- Used in industry
3
Q
Growth Curve for a Batch Culture
A
- Lag Phase: cells acclimating to medium and conditions. Time is variable
- Log Phase: cells grow with set generation time (aka doubling time). Fastest growth. Straight line (y-axis log scale). Slope depends on medium
- Stationary Phase: Viable count stays fairly constant. Death rate = growth rate. Cryptic growth. Decline in nutrient levels, increase in waste levels
- Death Phase/Decline Phase: Viable count decreases. Some cells may be hibernating. Nutrients exhausted. Waste builds up to toxic levels.
