Lecture 5 Flashcards
(14 cards)
Prototrophs
Heterotroph which can synthesize all its basic organic cell constituents (nucleotides, amino acids, vitamins, etc.) from a simple organic carbon source and inorganic salts
What medium do prototrophs grow on?
Simple and defined (often minimal medium)
What is complex medium made of?
natural products exact composition is unknown
Where do bacteria with unwown growth requirements grow?
On complex medium
Axenic Growth
Bacteria growing on simple or complex media and in the absence of other organisms
What is generation time
Time it takes cells to double (time between cell divisions)
When is generation time constant?
during exponential phase
What 4 things does generation time depend on?
temp, medium, aeration, mutations
Balanced Growth
Characteristic of cells undergoing exponential growth
Average properties of cells do not change over time in this phase
Light scattering proportional to:
cell concentration
How do we measure turbidity?
Using specrophotometer
How do you figure out how many cells are inculture after using spectrophetomer?
using serial diulations Diluting in a series of steps and plating are used to determine the number of viable cells in liquid culture
3 phases of growth?
Lag, exponential, stationary
Persistent viability of surviors
A step after stationary phase in which a select few cells will continue to survive
