AEST Agricultural Biotechnology Specialist Certification Practice Exam

The use of a streak plate in working with cell cultures is primarily a technique employed to isolate a pure strain from a species of microorganism. This method involves spreading a diluted microbial sample across the surface of an agar plate in a specific pattern. As a result, individual cells are separated from one another. Over time, these cells grow and form distinct colonies. Each colony arises from a single cell, allowing researchers to obtain a pure culture of that specific microorganism.

This practice is fundamental in microbiology and agricultural biotechnology because isolating pure strains is essential for studying the characteristics, behaviors, and applications of specific microorganisms. It enhances the ability to identify beneficial traits or pathogenicity in organisms, serving critical roles in research, medicine, agriculture, and industry.

In contrast, the other options do not align with the primary purpose of a streak plate. Measuring microbial growth rates involves different techniques, such as optical density measurement or viable cell counting, which assess how many cells are present over time. Assessing nutrient content typically requires additional biochemical assays and does not directly relate to the streak plate method. Additionally, cultivating multiple strains simultaneously may be conducted using methods such as co-culturing or mixed media, which differ significantly from the isolation-focused approach of the streak plate technique.