aseptic technique and lab skills
Why must an inoculating loop be flamed until red-hot in a Bunsen burner before and after streaking agar?
To sterilize the loop with heat and kill unwanted microbes (preventing cross-contamination).
What is the major difference between the lytic cycle and the lysogenic cycle of a virus?
In the lytic cycle, the virus actively destroys the host cell quickly. In the lysogenic cycle, viral DNA integrates into the host genome and remains dormant.
What type of symbiotic relationship exists between gut bacteria that synthesize Vitamin K and the human body?
Mutualism.
What is the term for using living microorganisms (like bacteria) to clean up environmental pollutants like oil spills?
Bioremediation.
What does a clear zone (zone of inhibition) around a disinfectant-soaked paper disc on an agar plate indicate?
It shows the effectiveness of the chemical agent in inhibiting or preventing bacterial growth.
Why are antibiotics completely ineffective against viral infections such as influenza or the common cold?
Antibiotics target bacterial structures (e.g., cell walls, bacterial ribosomes) which viruses do not possess.
What is a major side effect of prolonged, broad-spectrum antibiotic use on the human digestive system?
It destroys beneficial gut flora (good bacteria), leading to digestive issues or opportunistic infections.
Explain how stopping an antibiotic prescription early contributes to the evolution of antibiotic-resistant superbugs.
Only weak bacteria are killed early on. The most resistant bacteria survive, multiply, and pass on their resistance genes.
A student leaves their Petri dish lid wide open on the lab bench for 5 minutes while talking to a classmate. Is this an example or a non-example of aseptic technique? Explain.
A non-example. It exposes the sterile agar to airborne environmental contaminants and bacteria.
Name the two basic components found in all viruses
Genetic material (DNA or RNA) and a protein coat (capsid).
What is the key difference between a probiotic and a prebiotic?
Probiotics are live beneficial bacteria; prebiotics are dietary fibers that feed and nourish those good bacteria.
What small, circular ring of bacterial DNA is commonly used in genetic engineering to transfer resistance genes or produce human insulin?
A plasmid.