Module 3 Poll and Assigment questions Flashcards
You are studying the metabolism of new bacterium. If you are looking at how the bacterium synthesizes complex molecules, you are studying:
a. catabolism
b. anabolism
c. biosynthesis
d. anabolism and biosynthesis
d.
You want to isolate chemoorganoautotrophs from a mixed culture that also contains photoautotroph. What growth conditions would select for chemoorganoautotroph?
a. in the dark and the absence of a carbon source in the growth medium (CO2 is present in atmosphere)
b. In the dark and the presence of a carbon source in the growth medium
c. In the presence of light and the presence of a carbon source in the growth medium
d. in the presence of light and the absence of a carbon source in the growth medium (CO2 is present in atmosphere)
a.
Which organic compound(s) can provide every to bacteria?
a. glucose
b. cellulose
c. DNA
d. Milk casein
e. milk fat
f. All of the above
F.
If you grow bacteria in the presence of ammonium and sulfate, what type of metabolic class and metabolism would you select for?
a. chemolithitrophy and anaerobic respiration
b. chemolithotrophy and aerobic respiration
c. chemoorganotrophy and anaerobic respiration
d. chemoorganotrophy and aerobic respiration
a. ammonium and sulfate are inorganic chemicals
Which of the following is not a condition for fermentation to occur?
a. insufficient amount of appropriate final electron acceptor
b. absence of genes encoding complexes and electron carriers in the electron transport system
c. incomplete krebs/TCA cycle
d. Presence of an inorganic electron donor
d.
What should you include in the medium for the bacterium that relies solely on fermentation to achieve the same energy production as the bacterium that uses anaerobic respiration?
a. a larger quantity of electron acceptor
b. a larger quantity of organic electron donor
c. more oxygen
d. A larger quantity of inorganic electron donor
b.
If you omit a source of nitrogen and a source of carbon in your growth medium, what type of bacteria will grow under these conditions?
a. heterotrophs with a calvin cycle
b. autotrophs with reverse citric acid cycle
c. autotrophs that fix nitrogen
d. hetertrophs that fix nitrogen
c.
What is the most common type of cell division in bacteria?
a. budding
b. binary fission
c. mitosis
d. fragmentation
b.
You observe ghost cells in your bacterial culture. What is the best explanation?
a. bacteria are ejecting their DNA due to sporulation
b. These bacterial cells are dead
c. The z-ring is formed prior to segregation during the cell division cycle
d. all of the above
c.
At which step can you inhibit biofilm formation?
a. attachment
b. colonization
c. development
d. dispersal
a.
which of the following would result in doubling of the population?
a. sporulation
b. cell death
c. budding division
d. formation of myxospores
e. germination
f. formation of chlamydia elementary bodies
c.
Which of the following methods would be used to measure the concentration of bacterial contamination in processed peanut butter?
a. total plate count
b. direct counting of bacteria on a calibrated slide under the microscope
c. turbitidy measurement
d. Dry weight measurement
a. able to dilute and only viable things will grow
During which phase would antibiotics be most effective?
a. lag phase
b. log/exponential phase
c. stationary phase
d. death phase
b. antibiotics are effective against actively growing cells
Below are bacterial species and their generation time. Which is the fastest growing bacterial species?
a. E. coli -20 mins
b. Bacillus cereus -10 mins
c. Streptococcus mutans -30 mins
d. mycobacterium tuberculosis -24 hours
b.
If you start bacterial culture with one bacterial cell, how many cells would be expected after 12 hours if one generation time is 1 hour.
a. 12
b. 720
c. 2048
d. 4096
e. many billions
d.
What needs to be added to your growth medium to meet the requirement of a chemoorganoheterotroph?
a. a source of organic carbon
b. a source of organic electron donor
c. a source of fixed inorganic nitrogen
d. all of the above
e. none of the above
d.
Which medium would you use to select against a tryptophan auxotroph
a. complex medium
b. defined medium without tryptophan
c. selective medium with tryptophan
d. differential medium with tryptophan
b. selecting against = don’t want it to grow
What type of metabolic classes are found in obligate/strict aerobes?
a. chemoorganotroph with aerobic, anaerobic respiration and fermentation
b. Chemoorganotroph with aerobic respiration and chemolithotroph with aerobic respiration
c. chemoorganotroph with anaerobic respiration and fermentation
d. chemoorganotroph with anaerobic respiration and lithotroph with anaerobic respiration
b.
What is the best explanation for lack of growth by microaerophile at high oxygen concentration?
a. respiratory chain of microaerophiles have low affinity towards oxygen
b. have incomplete defense against reactive oxygen species
c. do not have any defense against reactive oxygen species
d. do not have a respiratory chain that use oxygen as the terminal electron acceptor
b.
You want to isolate a strict anaerobic halotolerant neutrophile from a mixed culture. What growth condition would select for a strict anaerobic halotolerant neutrophile?
a. medium containing 0.5M NaCl at pH 7 and grown in a candle jar
b. medium containing 10M NaCl at pH 7 and grown in a candle jar
c. medium containing 0.5M NaCl and grown under atmospheric conditions
d. Medium containing 0.1M NaCl at pH 7 and grown in a candle jar
a
Match the description with the type of media:
Descriptions:
a. restrict bacteria growth and classify bacteria
b. precise composition of the medium is known
c. restricts the growth of specific bacteria
d. helps distinguish and classify bacteria
e. exact composition is unknown
f. meets the mininum needs of a bacteria to grow
types of media:
a. defined medium
b. differential medium
c. selective medium
d. selective differential medium
e. complex medium
f. minimal medium
a-d
b-e
c-c
d-b
e-e
f-f
Categorize the following measurements of bacterial growth based on living cells or total population (dead and alive)
Viable count
Coulter counter
turbidimetric -optical density
direct microscopy with grid
most probable number
Living:
-Viable count
-Most probable number
Total population (dead and alive)
-Turbidimetric (optical density)
-Coulter counter
-Direct microscopy with grid
Describe the 4 growth phases of bacteria
Lag phase:
-bacteria are adapting to their new environment and their is no increase in the number of living cells
Log phase:
-Bacteria are rapidly growing and population of living cells increases exponentially
Stationary phase:
-Growth slows down; bacteria death is equal to bacterial division
Death phase:
-Bacteria are dying at a higher rate than their growth
Order the following bacteria (most to least sensitive) of salt concentrations:
Halophiles
Halotolerants
Non-halophiles
Hyper-halophiles
Non-halophiles
Halotolerants
Halophiles
Hyper-halophiles
Match the terms with their definition:
Terms:
Oligotroph
Prototroph
Copiotroph
Auxotroph
Definitions:
-Grow in high levels of nutrient
-Requires the additions of macromolecules
-Requires low nutrient levels to grow
-Generate their own macromolecules from basic elements
Oligotroph: requires low nutrient level to grow (high nutrient level prevents growth)
Prototroph: self sufficient-generate their own macromolecules form basic elements
Copiotroph: grow in high levels of nutrient
Auxotroph: requires the addition of macromolecules because it does not synthesize them
Explain the process of bacterial cell division cycle
Chromosome replication:
- Chromosome is duplicated resulting in a bacterial cell with 2 chromosome
Elongation:
-The cell wall, membrane(s) and cytoplasm expand resulting in a longer/larger bacterial cell with 2 chromosomes
Segregation:
-Each copy of the chromosome are moved to a different pole resulting in longer/larger cell with a chromosome at each pole
Z-ring formation:
-The septum starts forming resulting in a longer/larger cell with cleavage furrow and a chromosome at each pole
Division;
-The septum closes resulting in 2 identical cells of “normal” size
Match the pathways (anaerobic/aerobic respiration, fermentation) with their terminal electron acceptors (ferric iron, oxygen, pyruvate)
Anaerobic: ferric iron
Aerobic: oxygen
Fermentation: Pyruvate
What are the oxygen requirements for the following:
Microaerophiles
Obligate aerobes
Aerotolerant anaerobes
Obligate anaerobes
facultative anaerobes
Microaerophiles: aerobic respiration only
Obligate aerobes: aerobic respiration only
Aerotolerant anaerobes: fermentation only
Obligate anaerobes: anaerobic respiration and/or fermentation
Facultative anaerobes: aerobic respiration and fermentation
What are the steps of biofilm formation
- reversible attachment
- irreversible attachment
- growth
- maturation
- detachment/dispersion
