UTA Microbiology Exam 3|221
Questions with Solutions
4 Basic Steps of binary fission - -1. Growth of cell size
2. Replication of DNA
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 appropriate for the use
of antibiotics? - -Log phase
- Following the death phase of the growth curve, ____ cells are considered
the surviving cells & are considered clinically important due to their
association with chronic infections, such as Tuberculosis. - -Persisters
- 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
- Open System Cultures - --Nutrients and air are replenished
-Dead cells and waste are removed
-Beneficial for industrial microbiology
- Microscopic Cell Count - -Cells are counted under a microscope using a
laser etched slide
- In using the direct microscopic cell count method, you will be able to
distinguish between live vs dead cells. - -False
- Fluorescence Staining - -Cells are counted under a microscope or flow
cytometer
, - In fluorescent staining, the end product results in live cells staining
___________? - -Green
- In fluorescent staining, the end product results in dead cells staining
___________? - -Red
- 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 count method?
- -Living
- Countable Range - -30-300 CFU/ml
- Optical Density - --Measured with spectrophotometer
-Light is passed thru culture and measured on other side
- Which method of measuring growth is considered an indirect approach? - -
Optical density
- Which method of measuring growth can be used on living or dead cells? - -
Fluorescent stain
- How is the pour plate technique set up? - -The sample is mixed with a
warm agar ranging from 45-50 C, poured onto sterile plated and swirled to
mix
- How is the spread plate technique set up? - -The sample is poured onto a
solid medium and spread using a L spreader
- What cell counting method is used for counting colonies from drinking
water? - -Membrane filtration
- What method of measuring growth is used in food/water testing? - -MPN
(most probable number)
- Steps of Biofilm Formation - -1. Attachment of planktonic cells
2. Cells become sessile
3. Growth & Division on substrate
4. Production of extracellular polymeric substance
5. Attachment of secondary colonizers & dispersion
- Quorum Sensing - -Cell to cell communication regarding cell density
Questions with Solutions
4 Basic Steps of binary fission - -1. Growth of cell size
2. Replication of DNA
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 appropriate for the use
of antibiotics? - -Log phase
- Following the death phase of the growth curve, ____ cells are considered
the surviving cells & are considered clinically important due to their
association with chronic infections, such as Tuberculosis. - -Persisters
- 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
- Open System Cultures - --Nutrients and air are replenished
-Dead cells and waste are removed
-Beneficial for industrial microbiology
- Microscopic Cell Count - -Cells are counted under a microscope using a
laser etched slide
- In using the direct microscopic cell count method, you will be able to
distinguish between live vs dead cells. - -False
- Fluorescence Staining - -Cells are counted under a microscope or flow
cytometer
, - In fluorescent staining, the end product results in live cells staining
___________? - -Green
- In fluorescent staining, the end product results in dead cells staining
___________? - -Red
- 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 count method?
- -Living
- Countable Range - -30-300 CFU/ml
- Optical Density - --Measured with spectrophotometer
-Light is passed thru culture and measured on other side
- Which method of measuring growth is considered an indirect approach? - -
Optical density
- Which method of measuring growth can be used on living or dead cells? - -
Fluorescent stain
- How is the pour plate technique set up? - -The sample is mixed with a
warm agar ranging from 45-50 C, poured onto sterile plated and swirled to
mix
- How is the spread plate technique set up? - -The sample is poured onto a
solid medium and spread using a L spreader
- What cell counting method is used for counting colonies from drinking
water? - -Membrane filtration
- What method of measuring growth is used in food/water testing? - -MPN
(most probable number)
- Steps of Biofilm Formation - -1. Attachment of planktonic cells
2. Cells become sessile
3. Growth & Division on substrate
4. Production of extracellular polymeric substance
5. Attachment of secondary colonizers & dispersion
- Quorum Sensing - -Cell to cell communication regarding cell density
