1. Growth of cell size
2. Replication of DNA
4 Basic Steps of binary fission
3. Division of cytoplasm
4. Septum formation & cell division
Z Ring Assembly FtsZ assembles Z ring to form divisome
Generation Time time it takes to double the population
Lag Phase Cells adjust to culture medium; no change in population
What factors determine the duration of the lag phase? Genetic makeup, media composition, initial inoculum size
During which phase of the growth curve is it most appro-
Log phase
priate for the use of antibiotics?
Following the death phase of the growth curve,
cells are considered the surviving cells & are considered
Persisters
clinically important due to their association with chronic
infections, such as Tuberculosis.
Log Phase Binary fission occurs; cell replication > cell death
Stationary Phase Resources become depleted; cell respiration=cell death
Death Phase Endospores can form; cell replication < cell death
Close System Cultures Have finite resources
-Nutrients and air are replenished
Open System Cultures -Dead cells and waste are removed
-Beneficial for industrial microbiology
Cells are counted under a microscope using a laser etched
Microscopic Cell Count
slide
In using the direct microscopic cell count method, you will
False
be able to distinguish between live vs dead cells.
Fluorescence Staining Cells are counted under a microscope or flow cytometer
, UTA Microbiology Exam 3 Test Questions and Answers Graded A+
In fluorescent staining, the end product results in live cells
Green
staining ?
In fluorescent staining, the end product results in dead
Red
cells staining ?
Coulter counting Detects electrical resistance change due to cell density
Viable Cell Counts Samples are diluted and grown on solid media
What type of cells are counted when using the viable plate
Living
count method?
Countable Range 30-300 CFU/ml
-Measured with spectrophotometer
Optical Density
-Light is passed thru culture and measured on other side
Which method of measuring growth is considered an
Optical density
indirect approach?
Which method of measuring growth can be used on living
Fluorescent stain
or dead cells?
The sample is mixed with a warm agar ranging from 45-50
How is the pour plate technique set up?
C, poured onto sterile plated and swirled to mix
The sample is poured onto a solid medium and spread
How is the spread plate technique set up?
using a L spreader
What cell counting method is used for counting colonies
Membrane filtration
from drinking water?
What method of measuring growth is used in food/water
MPN (most probable number)
testing?
1. Attachment of planktonic cells
Steps of Biofilm Formation 2. Cells become sessile
3. Growth & Division on substrate