Lecture 9 Flashcards
Lag Phase
Adaption to new growth conditions. Base of the line. Straight. Not many cells
Exponential Phase
Exponential Growth from binary fission
Stationary Phase
Starvation begins to happen and organisms eat the dead ones. Straight line
Death Phase
More cells die than divide. Negative slope
Growth Rate Constant
u in Nt=N0e^ut (/hr)
Generation Time
time taken for a cell population to double in numbers and thus equivalent to the average length of the cell cycle
Primary Metabolite
Directly involved in normal growth, development, and reproduction. Produced during the exponential phase
Persister Cells
Good at surviving, alive, not dividing, metabolism slowed down, but they aren’t mutants
Batch Culture
In a Flask. Waste builds up and can trigger the starvation phase. Only nutrients provided at the beginnings. Nutrients runs out. Cells are too crowded to get O2. Growth: lag, exponential, stationary, and decline. U- intrinsic
Continuous Culture
In Chemostat. Nutrients are continuously added. and waste is being released when nutrients are added. Growth: binary fission, but cell numbers are at equilibrium. U= adjustable by adjusting nutrient rate. Exponential phase
Chemostat
Complex system. used in continuous cultures. Nutrient is added and waste is released.
Direct Cell Count
Counts all cells, living and dead. cells/mL. Petroff-Hauser chamber & Coulter counter
Petroff-Hauser Chamber
Where you count cells that are in a grid square. Can’t use it if they are moving. Its a narrow range.
Coulter Counter
Interruption of electric current as cells pass through counter. Only particulates in solution are bacteria. Count dead and alive cells
Viable Cell Count
Counts only live cells. (cells that can grow) Colony Forming units/mL. Dilution and plating, filter plating, MPN
Pour Plate
Sample goes in the tray and liquid goes on top of it. and it grows either in 2D or in the liquid. Thats how you classify it
Spread Plate
Put diluted cultured on top of the agar. 0.1-0.2 mL max
Membrane Filter
Allows large volumes to be counted (like water). Poured through and the filter has pores that are .2um, so bacteria can’t get through. and then the filter paper is left and the bacteria grows on it
Most Probable Number (MPN)
Is a statistical method based on +/- growth in large numbers of test tubes at 3 different dilutions. 15 test tubes total
Turbidity (=optical density)
Based on optical density measurements with a spectrometer. More cells=more light scattered=higher OD. But cell shape is different so different cell shape scatters light differently
Biochip
biochips are essentially miniaturized laboratories that can perform hundreds or thousands of simultaneous biochemical reactions. Biochips enable researchers to quickly screen large numbers of biological analyses for a variety of purposes. Measure conductivity.
Conductivity
Measurement of cell products depends on metabolism of cells being studies. Acid of fermentation is easy to measure with a pH electrode. More protons = lower pH
Durham Tube
Gases are measured by Durham tubes. Gas collects at the bottom and then moves to the top of the mini tube in the big test tube
Luciderase
ATP can be measured by this reaction. Fireflies have this. Sometimes done to see if any viable cells remain in a culture. No ATP=no metabolism= dead cells
