true/false Flashcards
In water treatment process, the flocculation step uses a chemical such as alum to form aggregates with colloidal material.
True
The use of microorganisms to remove pollutants is called bioremediation.
TRUE
This stage of water treatment involves removal of solid matters called sludge. Biological activity is not important at this stage, and approximately 25%-35% of the Biological Oxygen Demand (BOD) is removed.’
The above statement BEST describe a water treatment stage that is called….
primary treatment of sewage.
The discharged water from tertiary wastewater treatment is usable for irrigation only.
FALSE
A culture of bacteria produces 8 generations in 4 hours. what is generation time of this bacteria?
30 minutes
One of the advantages of using agar in the isolation of bacteria is that only a few microbes can degrade agar, and therefore it remains solid.
TRUE
Selective media allow for the growth of multiple species of microorganisms while distinguishing them based on different reactions they produce, such as color changes or other observable characteristics.
FALSE
- differential media
Alcohol is a chemical agent that is preferably used for swabbing the skin before injection.
TRUE
The concentration of the material to be disinfected serves as an important factor in effective disinfection.
TRUE
The concentration of the material to be disinfected is an important factor in effective disinfection. Using the correct concentration ensures that the disinfectant is potent enough to kill or inactivate pathogens. Too low a concentration might be ineffective, while too high a concentration could be unnecessarily harsh or toxic. Therefore, following recommended guidelines for concentration is crucial for achieving optimal disinfection results.
Autoclave is a suitable method to sterilize heat labile (heat sensitive) solutions.
FALSE
Autoclaving is not suitable for sterilizing heat labile (heat sensitive) solutions because it involves high temperatures and pressure, which can degrade or destroy heat-sensitive substances. For heat labile solutions, alternative methods such as filtration or chemical sterilization (e.g., using ethylene oxide or peracetic acid) are more appropriate.
A spectrophotometer is used to estimate bacterial concentration by measuring turbidity, which is the amount of light passing through a suspension
TRUE
Short-term storage of bacterial cultures involves deep-freezing: a pure culture of microbes is placed in a suspending liquid and quick-frozen at temperatures ranging from –50°C to –95°C.
FALSE
What is the method use for short-term storage and long-term storage of bacterial culture? what is the different between each method?
Methane-producing bacteria are also found in the limnetic zone.
FALSE
Methane-producing bacteria, also known as methanogens, are typically found in anaerobic environments where they can produce methane as a byproduct of their metabolic processes. Such environments include the sediments of wetlands, rice paddies, and the digestive tracts of animals.
The limnetic zone of a lake is the well-lit, open water area away from the shore, and it is usually more oxygenated compared to the deeper, anoxic sediments where methanogens thrive. Therefore, methanogens are not commonly found in the limnetic zone.
‘Bacteria that do not use oxygen for growth but can survive and grow in its presence. Its growth occurs evenly in a tube of culture medium because oxygen has no effect on its growth’.
This statement describe which bacterial group?
aerotolerant anaerobes
How about other group of bacteria, Group A, B, C and E? Do you know how to describe the bacterial growth in a tube of growth media?
