Final answer:
The term that refers to the purposeful addition of microorganisms into a laboratory nutrient medium is inoculation. It is the first step in a series of procedures that are essential for studying microorganisms, involving growing pure cultures and possibly fulfilling Koch's postulates. Therefore, the correct option is 1.
Step-by-step explanation:
The term that refers to the purposeful addition of microorganisms into a laboratory nutrient medium is inoculation. Inoculation is a critical step in microbiology that involves introducing a microorganism or a group of microorganisms to a nutrient medium designed to support their growth. This technique is essential for studying microorganisms under controlled laboratory conditions and is part of the broader process that includes isolation, incubation, and identification of microbes.
After inoculation, the organisms enter the lag phase, where they adjust to the new environment before starting to reproduce. The aim is to grow a pure culture of the microorganism to study its characteristics or to ensure it is the causative agent of diseases following Koch's postulates. These cultures are typically grown in liquid broth or on solid media in Petri dishes, under controlled environmental conditions that include optimal temperature, pH, and atmospheric gases.
Although culturing bacteria in the laboratory is complex, with less than 1% of bacteria being cultivable, microbiologists have developed selective techniques to enrich and isolate the types that can be cultured. By providing the appropriate food, water, and environmental conditions, they can reproduce these selected populations for various studies and applications in microbiology and related fields. This understanding is crucial for tasks such as investigating food safety and diagnosing infections.